On March 10, 2011, Chairman Wu Bangguo of the standing committee of China's National People's Congress announced that a socialist law system with Chinese characteristics has formed, but the legal system can be constructed through legislation to form? What meanings are vocabularies that describe the characteristics of the legal system of socialism with Chinese characteristics? And what is the evaluation criterion of this system? To answer these questions, in this paper, we combine the key laws in the key point and the legal disputes between scholars in the forming process of the legal system of socialism with Chinese characteristics, trying to sketch a picture of pure and fresh and full of historical composition and theoretical framework.Core idea of this article think, first, the constitution i plays a fundamental role in the formation of the legal system of socialism with Chinese characteristics. Whether the constitution itself is good or bad determines the content and value of the system, also determines the path and the historical track of the formation of the system. China's National People's Congress (NPC) as the main architect of this system, whose behavior is restricted by the constitution. Second, although all previous changes to the Chinese constitution, which are the result of the development of social politics economy and culture in China, but deepened people’s understand to the law in China, led to scientific discussion of the legal system, and thus indirectly affect the content of the legal system of socialism with Chinese characteristics. Furthermore, we think that the formation of the legal system of socialism with Chinese characteristics in fact is the result of benign operation of constitutionalism under the guidance of the constitution in China.First of all, the legal system was proposed based on the needs of the legislation, and analyzed the social cause to the concept. Second, Chinese scholars on the legal system of tong said, which is to point to by a country's current legal norms, formed by the combination according to different classification of legal department of a systematic organic connection of the unified whole. Through the analysis, we think it boils down to law system, in essence is a normative system. It lasted for the basic ideas of analytical positivism jurisprudence, its biggest function is to guide legislators classify legislation, by looking for omissions, additions, so can effective legislation in a short period of time. At the same time, it also facilitates law student learning, and provides direction for their future work in the legal fields. In thought, law system highlights the national centralism construction view, emphasized the national rationality, maintenance of the constitution established the people's congress system, set up the center of the National People's Congress and its standing committee at all levels. The constructivism too believes that the role of human reason. Again, through the use of historical material, analyses the formation of the legal system of socialism with Chinese characteristics has undergone a preliminary formation, the basic form, and then to the final forming process. While the theory of socialist legal system with Chinese characteristics has experienced a "socialist legal system", "legal system of socialist market economy", "the legal system of socialism with Chinese characteristics" between transformation of space and time. Between the key combed the Chinese officials and scholars discussing the standard about legal system formed, because this is a major theoretical issues in construction of legal system. After analyzing various views, point that the constitution is in the core position in the formation of the legal system of socialism with Chinese characteristics, if considering t the constitution should be brought into the formation of legal system, and care to the codification of China tradition, criterion of formation can be summed up in four: (1) whether the full implementation of the provisions of the constitution as the legislation; (2) the basic law of law department has codified ; (3) respect for human rights; (4) the unity of legal system. Although the legislation is a difficult task, but compared to law enforcement of the legal system, it is relatively easy. When legislation is not largely enacted, legal interpretation, especially the judicial function becomes increasingly obvious. These are all challenges for China in the future.