Patriarchal power and theocracy's protection to imperial power. According to relevant data, the ancestral temple and the social altar in front of the Wumen Gate of the Forbidden City, an ancient building in China, show the protection of the imperial power by clan power and theocracy. The central axis of Beijing is the material expression and external symbol of China's traditional etiquette culture. Buildings located in different directions have different functions, which are restricted by the political system and the matching social consciousness. As a palace, the Forbidden City is located in the center of the axis, with Wenhua Hall and Wuying Hall on both sides. The ancestral temple and the social altar are in front of the palace, showing the protection of the imperial power by the clan power and theocracy. The "six offices" located on both sides of Tiananmen Square show the centralized state rule.