“The combination of civil and commercial” has always been regarded as one of the important theories in the academic circles of our country. “The commercial law is the special law of the Civil Law” this kind of view almost became the classical theory of the academic circle. But the Commercial Act has its own particularity, and from the Civil Law System Country Legislation, the Commercial Act and the commercial subject are closely linked, the commercial law separates from the civil law gradually to form the separate legislation. Therefore, we should really understand the essence of commercial act from its concept, characteristics and the connection and difference with Civil Act, and construct the system according to the concept and principle of private law.