Mechanical system design is the backbone of the professional courses to cultivate innovative mechanical engineers and researchers．However,comprehensive contents and insufficient study hours，multi·disciplines andsuperficial understandings are the main contradictions for teaching of the course．This paper presents detailed analyses of the difference and similarity in contents between existing textbooks，and the relationship between the course and the other courses in the teaching program．The system design methodology is suggested as the core teaching subject for the curriculum，and some modem design methodology is proposed to be added to the course teaching contents．A detailed series of teaching objectives，teaching contents，teaching modes and teaching materials are presented．It emphases the development of students'ability to innovate is the main purpose of the course．