In order to win the trust of the people and fundamentally ensure the success of the reform, Shang Yang built a tree at the south gate to gain trust. He was undoubtedly successful. Not only did he establish a good image for the court of being true to his word and doing what he said, he also successfully laid a solid foundation for the implementation of the new law, and even established a sense of "integrity" throughout the country. Abiding by the law and doing what you say you will do” is a good social atmosphere. We must also learn from Shang Yang, "words must be deeded, deeds must be resolute", and we must keep our promises and do what we say.