Politically, Emperor Taizong was able to know people and be good at their duties. First of all, he set up an efficient leadership team for himself and created a clear political atmosphere. He listened to people's advice all his life and was passed down as a historical story. According to records, Wei Zhi alone lectured him more than 200 times. Instead of being angry, he became more modest and willing to make suggestions, and regarded Wei Zhi as a mirror of gains and losses. In order to consolidate his rule, he further improved the system of three provinces and six departments, greatly improved the administrative efficiency of * * * *, and vigorously developed the imperial examination system, trained talents, expanded the ruling foundation of * * *, and consolidated centralization.

Economically, Emperor Taizong knew that agriculture was the foundation of the national economy. As soon as he took office, he promulgated a series of policies concerning taxation and rest to encourage agricultural development. In addition, in his early years, he witnessed the extravagance of Emperor Yang Di and the oppression and slavery suffered by the people at the bottom. He is determined to cherish the people's resources and never refuses to levy corvee easily. Even though he suffers from Qi disease and is not suitable to live in a damp old palace, he still refuses to spend the people's efforts to build a new palace. This quality of being strict with oneself and being lenient with others has won him unanimous love and support from top to bottom. Therefore, under the leadership of Emperor Taizong, Zhen Guan was harmonious and the economic development situation improved rapidly. By the eighth to ninth year of Zhenguan (634 ~ 635), cattle and horses were everywhere, the people were well-fed and well-fed, the doors were not closed at night, and the roads were not picked up, which was a scene of prosperity and peace.

Emperor Taizong devoted his whole life to benevolent government and attached great importance to the rule of law. Even in the hierarchical feudal society, he insisted on upholding the justice of the law and set an example for promoting the rule of law. He once said to his men: the national law is not the law of the emperor alone, but the law that everyone in the world must abide by, so everything must obey the law.

In Zhenguan, the prince committed the same crime as the people, and enforced the law strictly, but he was very cautious when sentencing, because Emperor Taizong was kind-hearted and always told law enforcement officers: people can't be resurrected after death, and law enforcement must be lenient. Under his painstaking efforts, the legal system was very good during the Zhenguan period, and the number of traitor crimes was greatly reduced. According to historical records, in the third year of Zhenguan (629), only 29 people were sentenced to death, almost to the point of not relying on punishment.

During the twenty-three years of Emperor Taizong's reign in Li Shimin, the social productive forces in the Tang Dynasty achieved great development, with unprecedented economic prosperity, social stability and political clarity. The Tang Dynasty became the most powerful empire in the world at that time, while Chang 'an was a cosmopolitan metropolis, attracting vendors and literati from all over the world. The Tang Dynasty was also an open country. Envoys and envoys of various countries, after witnessing the prosperous times of the Tang Dynasty, brought the highly developed culture and technology of the Tang Dynasty to all parts of the world and made outstanding contributions to the development of the whole world civilization. Therefore, in history, the rule of Emperor Taizong and Li Shimin was called the rule of Zhenguan, which was not only the most powerful historical period of the Tang Dynasty, but also the most brilliant memory in the history of China feudal dynasty.