After Qin Shihuang unified China, the enfeoffment system was abolished nationwide and replaced by the county system. Under the direct control of the emperor, a whole set of bureaucracy from the central government to the counties was established, and the authority and centralization of the central government were established. In addition to the reform of the political system, Qin Shihuang also widely unified other systems, including the national land and water transportation system (cars on the same rail), the national writing system (books and characters), the national weights and measures system (scales) and the national monetary system (money and coins). He also tried to unify the whole country's thoughts (burning books and burying Confucianism), but it was not completed because of violence (the unification of thoughts was not completed until Emperor Wu of the Han Dynasty "ousted a hundred schools of thought and respected Confucianism alone"). It should be said that it is precisely because Qin Shihuang paid attention to the rule and system construction of conquered land, unlike other conquerors of his time (such as Alexander of Macedon or Caesar of Rome), that unified land rule was stabilized, and China did not experience truly irreversible division or extinction like other ancient civilizations in the next few thousand years, which laid a historical foundation for the territory of modern China.
Qin Shihuang initiated the post station system and built the post road, which laid the technical foundation for the decree access of the huge empire and the resulting county-based empire. "Building a post road and setting up a county" is a necessary condition for China to adopt the advanced county system to replace the western enfeoffment system. At the same time, Rome can't effectively control the occupied areas, and there is only one powerful governor (the governor is in charge of the military and political power of a place, all of whom are nobles, and the grass-roots organizations rely on the original local organizations), which is still similar to the enfeoffment system, which is a very important reason for the later division of the Roman Empire. The county system is a civilian system, and its military and political leaders are appointed by the emperor. According to their political achievements, their military achievements can be raised or lowered and leveled, which leads to the emergence of professional bureaucrats and professional soldiers. Professional bureaucrats and professional soldiers can come from civilians, and the county bureaucracy effectively guarantees the rights of civilians (cloth) to participate in and discuss state affairs (for example, Reese and Meng Ao, both of whom are cloth, can only stand out according to military merit). Compared with the feudal aristocratic politics, it is undoubtedly a great historical progress. Some people think that both the civil service system and the military system of modern countries originate from this.
Since Shang Yang's political reform, Qin attached great importance to the rule of law. Qin Shihuang inherited this tradition and admired Han Fei, a legalist figure. He once lamented that "if you walk with him, you will have no hatred." During the war, Qin Shihuang rewarded and punished the generals according to law. After the unification of China, Qin Shihuang absorbed some provisions of the laws of six countries on the basis of the original laws and decrees of Qin State, and formulated and promulgated unified laws throughout the country. Although Qin Shihuang was autocratic and thought that "we rule the world", he still ruled the country according to law in the Qin Dynasty. The reason for the Guangwu Chen Sheng Uprising was that the Qin law was harsh and sinful, so we had to rebel. It is "the law forces the people to revolt", not the "official forces the people to revolt" caused by such serious corruption as "the wine and meat in Zhumen stink and the road freezes people to death" in later generations. Some people think that later Confucianism advocated the rule of man by enlightenment, the rule of country by human etiquette rather than law, and even the rule of monarch, which led to the wind of rule of man and flattery still existing.