The reasons for countries to determine their National Day are various. According to statistics, there are 35 countries that take the time of the country's establishment as National Day. Some countries like Cuba and Cambodia take the day when the capital was captured as National Day. Some countries take the day of national independence as National Day. On January 1, 1804, the Haitian people defeated Napoleon's 60,000 expeditionary forces in Port-au-Prince and declared independence, so they set January 1 as National Day every year. Mexico, Ghana and other countries are also the same. Some countries take the anniversary of an armed uprising as National Day. July 14 is the French National Day. On this day in 1789, the people of Paris attacked the Bastille, a symbol of feudal rule, and overthrew the monarchy. Some countries take the date of a major meeting as National Day. The United States takes July 4, 1776, the day when the Continental Congress adopted the Declaration of Independence, as its National Day. Canada takes July 1, 1867, the day when the British Parliament passed the British North America Act, as its National Day. There are also countries that take the birthday of the head of state as National Day, such as Nepal, Thailand, Sweden, the Netherlands, Denmark, Belgium, etc.

In September 1949, the first session of the Chinese People's Political Consultative Conference decided to set October 1 as National Day. On October 1, 1949, the People's Republic of China was proclaimed, which marked the most significant transformation in Chinese history. At 3 p.m. on October 1, 1949, 300,000 people in Beijing held a grand ceremony at Tiananmen Square to celebrate the founding of the Central People's Government of the People's Republic of China. Mao solemnly announced the establishment of the People's Republic of China and the Central People's Government, and personally raised the first Five-Star Red Flag. Mao read the "Announcement of the Central People's Government of the People's Republic of China": "The Central People's Government of the People's Republic of China is the only legitimate government representing the Chinese people. The government is willing to establish diplomatic relations with any foreign government that is willing to abide by the principles of equality, mutual benefit, and respect for territorial sovereignty." Then a military parade and mass procession were held. General Zhu inspected the naval, land, and air forces and announced the "Order of the Headquarters of the Chinese People's Liberation Army," ordering the Chinese People's Liberation Army to quickly eliminate all remaining Kuomintang armed forces and liberate all unliberated territories. On the same day, the Beijing Xinhua Broadcasting Station broadcast the live coverage of the inauguration ceremony of the People's Republic of China at Tiananmen Square. This was the first large-scale live broadcast in the history of Chinese radio broadcasting, and all local radio stations across the country simultaneously broadcast it.