Legal supervision is not power, but a law ecology, just as restriction is not a special power. To understand the legal supervision of the People’s Procuratorate, we must change the concept of substantive right. Legal supervision is the constitutional duty of the People’s Procuratorate in our country. It is the effect of restraining power or the ecology of politics and rule of law realized by the People’s Procuratorate through the exercise of procuratorial power. Understanding the legal supervision from the perspective of the rule of law ecology is in line with the principle and spirit of establishing the People’s Procuratorate as the national legal supervision organ in the constitution, and also in line with the objective fact of restricting and supervising the power, which can better resolve many problems existing in the current procuratorial theory and practice. The construction of legal supervision ecology is not only the need of implementing the constitution, but also the need of promoting the modernization of national governance capacity and governance system. The People’s Procuratorate, as the state’s legal supervision organ, is the force to implement and promote the rule of law ecology.