National Day holidays are legal holidays established by a country to honor the country itself. They usually mark the anniversary of the country's independence, the signing of the constitution, the birth of the head of state, or other anniversaries of great significance; some are also the saints' days of the country's patron saint.

In 2023, the Mid-Autumn Festival and National Day holidays will be "combined" and will be held from September 29 to October 6 for eight days. During the National Day, highway traffic will be free.

The term "Guoqing" originally referred to national celebrations, and was first used in the Western Jin Dynasty. A writer named Lu Ji said in his book "five vassals" said， "There is no greater national celebration than the enthronement and birth of an emperor." In the feudal era of China, the most important events of national celebrations were the ascension to the throne and the birth of the emperor. Therefore, in ancient China, the emperor's accession to the throne and his birth date were called "National Day". Today, the anniversary of the establishment of the country is called National Day.

On December 2, 1949, the fourth meeting of the Central People's Government Committee accepted the proposal of the National Committee of the Chinese People's Political Consultative Conference (CPPCC) and adopted the "Resolution on the National Day of the People's Republic of China", which decided that October 1 every year would be the great day of the People's Republic of China's proclamation of the founding of the People's Republic of China as its National Day.

According to statistics, there are 35 countries in the world that celebrate their national day with the time of their founding. Some countries celebrate their national day on the day of the occupation of their capital city, such as Cuba and Cambodia. Some countries celebrate their national day on the day of independence.

On January 1, 1804, the Haitian people annihilated Napoleon's 60,000-strong expeditionary force and declared independence in Port-au-Prince, and since then they have designated January 1 of each year as their national day. The same is true for Mexico, Ghana and other countries. There are also some countries to the anniversary of the armed uprising as a national holiday. July 14 is the French national day. 

On this day in 1789, the people of Paris captured the Bastille, a symbol of feudal rule, and overthrew the monarchy. Other countries celebrate national holidays on the days of major conferences.

The United States takes July 4, 1776, the day the Continental Congress adopted the Declaration of Independence, as its national day. 

Canada celebrates its national day on July 1, 1867, the day the British Parliament passed the North America Act of Great Britain. There are also national days celebrated on the birthdays of heads of state, such as in Nepal, Thailand, Sweden, the Netherlands, Denmark and Belgium.

National Day is an important holiday in every country, but it has a different name. Many countries call it "National Day" ,while others call it "Independence Day", also called  "Republic Day", "Revolution Day", "Liberation Day", "National Rehabilitation Day", "Constitution Day", and so on, and there are also directly to the name of the country plus the "day", such as "Australia Day", "Pakistan Day", some to the king's birthday or enthronement day for the national day, such as the king change, the specific date of the national day also changed.

Although the vast majority of countries have a similar anniversary, but due to the complex political relations, some countries of this holiday can not be called national day, such as the United States only Independence Day, not national day, but both have the same meaning.

In ancient China, the emperor's accession to the throne, the birth anniversary is called "National Day". Nowadays, China's National Day refers to October 1, the anniversary of the founding of the People's Republic of China.

The oldest National Day in the world history is San Marino's National Day, as far back as 301 AD, San Marino will be September 3 as its own National Day.