First of all, the Qin Dynasty ended hundreds of years of war since the Spring and Autumn Period and the Warring States Period, and the whole country was unified, establishing the first unified multi-ethnic centralized country in China history. Among many vassal States of Qin, it is not the strongest. After Shang Yang's reform, he became one of the seven heroes, and after several generations of military commanders such as Qin, Zhou, Zhuang and Xiao, the burden of history finally fell on Qin. After he succeeded to the throne, he put down Lao Ai's rebellion, dismissed Lv Buwei, activated Liao Wei, Li Si and others, and continued to carry out the policy since Shang Yang's political reform, which promoted the political and economic development of Qin State and provided a solid foundation for reunification. Finally, in 22 1 BC, the unified war against the six countries was completed. After Qin's reunification, it continued to expand, attacked Xiongnu in the north, recovered Hetao area, and crossed the Yellow River to establish counties in the south of Yinshan Mountain. In the south, a unified war was waged against the areas inhabited by Baiyue tribes, and the "Lingnan three counties" such as Nanhai, Guilin and Xiang Jun were established, and they were extended to the southeast coastal areas under the rule of the central dynasty. At the same time, a canal is dug to connect the Pearl River water system with the Yangtze River water system and the economic and social development of the primary frontier areas. Qin has a vast territory, with Xianyang as the center, east to the sea, west to the edge of the Qinghai-Tibet Plateau, south to Lingnan and north to Liaodong, which really laid the foundation for China to unify a multi-ethnic country.
? Secondly, a series of political, economic and cultural systems initiated by the Qin Dynasty were later generations, which had a far-reaching impact on China's social development. After the unification of Qin Dynasty, the emperor system was established, and the autocratic monarchy was strengthened. Relevant regulations were made from the highest honorific title of "emperor" to the discussion of court, documents and costumes, which really put "respect for monarch" in the first place, thus establishing the absolute authority of the emperor and the ruling order that controls everything, that is, we usually say that the central power is concentrated in the hands of the emperor; Qin set up "three public officials and nine ministers" in the central government to assist the emperor in managing the country. Qin promoted the county system in place of feudalism. There are 36 counties in China, including counties, townships, pavilions and villages. In this way, the emperor's decrees can go directly to the county, county, township and village through the three public offices and nine ministries. This system initiated by the Qin Dynasty not only ensured the centralized imperial power system, but also denied the decentralized feudal system, which was followed by China's later dynasties. In order to ensure the centralization of authority to be vigorously promoted, Qin and Wei carried out a series of supporting reforms and constructions, such as building the Great Wall to defend the military, building imperial roads, developing Baiyue by immigrants, burning books to bury Confucianism and unified measurement's unified thought, and so on. These measures have accelerated the cohesion of the centripetal force of the Chinese nation, drawn concentric circles for the future development of multi-ethnic countries, and laid the foundation for the cultural identity of the Chinese nation.
? As can be seen from the above two points, although the meteor flashed through the Qin Dynasty, it shone in the night sky. From the superficial territory to the internal system construction, it opened the imperial road of centralized feudal monarchy in China's history for nearly two thousand years. As a short-lived dynasty, the demise of Qin has also become a historical reference. Many politicians and thinkers have tried their best to explore the reasons. Lu Jia's Xin Yu, Jia Yi's On Qin, etc. , are blamed on the "tyranny" of the qin dynasty. Qin used the martial arts of the founding of the country to govern the country, and the people were overwhelmed, which eventually led to poverty for the people. The painful lessons have alerted this later dynasty and become a negative teaching material, which can also be used.