The Zuo Zhuan states, "The major affairs of a state are sacrifice and warfare." Sacrifice was a crucial part of ancient Chinese ritual traditions, with an extensive and complex system. Royal sacrifices in ancient times had strict regulations concerning the objects of sacrifice, locations, and ceremonial procedures.

The Beijing Central Axis features four significant temples and altars: Imperial Ancestral Temple, Altar of Land and Grain, Temple of Heaven, and Altar of the God of Agriculture. These sites hold considerable value in terms of overall planning, architectural design, decorative art, and construction techniques. They also provide strong evidence of the ceremonial rituals and practices of ancient Chinese royal worship, reflecting the objects of worship, locations, and institutional ceremonies.

The worship objects of these four temples and altars can be primarily divided into three categories: heavenly deities, earth spirits, and ancestors and ghosts. These correspond to the three fundamental elements of ancient Chinese cosmology: Heaven, Earth, and Humanity. Heavenly deities include the Supreme God of Heaven, the sun, moon, stars, as well as wind, rain, thunder, and lightning. Earth spirits include deities of land and grain, as well as gods of mountains and rivers. Ancestors and ghosts include veneration of ancestors and other human-related deities.

Imperial Ancestral Temple

The Imperial Ancestral Temple is the most well-preserved and largest royal ancestral worship complex in China. Ancestral worship holds profound ethical significance in traditional Chinese society. This ritual not only reflects the cultural tradition of "reverence for heaven and the ancestors" and "aligning ancestors with heaven", but also symbolizes the legitimacy of dynastic rule being passed down within the family.

The Imperial Ancestral Temple is symmetrically arranged along the central axis with the Imperial Divine Temple, reflecting the ideal city layout described in the "Kaogongji" (Records on the examination of craftsmanship) with "ancestors on the left and earth on the right." Within the temple's walls, three main halls are aligned from south to north: the Sacrificial Hall, the Resting Hall, and the Distant Kin Temple. The Sacrificial Hall is the site for grand ancestral ceremonies conducted by the emperor and has the highest architectural form. The Resting Hall and the Distant Kin Temple, where ancestor tablets are "rested" daily, have similar architectural forms but are slightly less grand than the Sacrificial Hall.

Altar of Land and Grain

The Altar of Land and Grain is dedicated to the worship of the God of the Land and the God of Grain. As an agrarian nation, China's foundation lies in its land and grain. Worshiping these deities not only honors the land and crops but also symbolizes prayers for the nation's territorial integrity and stability. The Imperial Divine Temple thus links national and social order with human-land relationships.

The Altar of Land and Grain is located to the west of the Imperial Ancestral Temple and features both an inner and outer enclosure. The central altar is square-shaped, with its platform covered in five types of colored soil, commonly referred to as the "Five-Color Soil." This symbolizes multiple concepts such as the five directions and the five elements. The soil is collected from various regions across the country, representing the idea that "Kings have long arms".

Temple of Heaven

The Temple of Heaven is dedicated to the worship of the Supreme God of Heaven. Offering sacrifices to Heaven is a key manifestation of the ancient belief in the "divine right of kings," indicating that the emperor is ordained by Heaven and holds a sacred status.

The Temple of Heaven features two concentric enclosures with a circular northern section and a square southern section, symbolizing the ancient cosmological view of "Heaven is round and Earth is square." Inside, there are two main altars: the Circular Mound Altar on the south side and the Altar of Prayer for Good Harvests on the north side, which includes the Hall of Prayer for Good Harvests. Both altars were used by the Ming and Qing emperors for heaven worship, but they served different purposes, and were used at different times, and involved distinct ceremonial processes.

The design of the altars at the Temple of Heaven reflects their function of heaven worship. Both core altars are circular, in contrast to the square altars used for earth worship. Each altar consists of three tiers that taper upwards. For the Circular Mound Altar, both the number of balustrades and steps at each tier are odd numbers, aligning with the theme of heaven worship. The Hall of Prayer for Good Harvests features a circular, pointed roof and is covered with blue glazed tiles, which is distinct from the more commonly used yellow, green, or black glazed tiles in imperial architecture. The blue tiles symbolize the sky.

Altar of the God of Agriculture

The "Book of Rites" records, "The emperor personally plows in the southern suburbs to ensure a bountiful harvest." The selection of the site for the Altar of the God of Agriculture follows this unique tradition of personal farming in the southern suburbs.

During the Ming and Qing dynasties, the Altar of the God of Agriculture hosted three different types of sacrificial activities. Within the inner altar area, the Altar of the God of Agriculture, the Imperial Field, and the Viewing Platform  together formed a ceremonial complex for the plowing ritual, where the emperor personally engaged in farming ceremonies. The Altar of the God of Agriculture was dedicated to the worship of the agricultural deity Shennong. The Imperial Field, a ceremonial plot of one mu and three fen (from which the saying "one mu and three fen" originates), was used for the emperor and high officials to perform the plowing ritual. The Viewing Platform was used by the emperor to observe high officials performing the plowing. To the north of the inner altar area is the Tai Sui Hall, used for worshiping the God of the Year and the Twelve Month Gods. In the southern part of the outer altar, the Altar of Deities was used for worshiping heavenly deities (such as gods of wind, rain, thunder, and lightning) and earth spirits (such as deities of mountains, rivers, and seas).

The emperor's personal plowing, through the worship of agricultural deities, demonstrated the state's emphasis on agricultural activities. Especially during the Qing Dynasty, where the ruling class was originally nomadic, the increased frequency of such rituals aimed to show respect for farming culture and soothe public sentiment. During the Ming Dynasty, emperors personally plowed or sent officials to conduct rituals 34 times. In contrast, the Qing Dynasty saw 247 such events, with 58 ceremonies occurring during both the Kangxi and Qianlong reigns.