Abstract: Due to the limitation of teaching thoughts and practice means used by the traditional mechanical design practice teaching system, it is not advantage to the cultivation of innovation ability of students. Therefore, it is urgent to reconstruct the mechanical design practice teaching system. Several critical issues are discussed for the reconstruction of mechanical design practice teaching system. The effect of system reconstruction on the cultivation of innovation ability of students is analyzed. The innovation philosophy is that the mechanical design practice teaching system is constructed under the thoughts of thorough cognition of mechanical design. It is completed by adding a computer aided design item. This item emphasizes on the ability cultivation of three-dimension design for students. It is useful to break the obstacle among the practice in class, course design and discipline competition out of class. Results indicate that the reconstruction of practice teaching system combined the mechanical design practice with the social requirements and the discipline competition. The issues selection of mechanical design is broadened. The application of three dimension soft in the mechanical design is pushed. The ability of putting the theory into action is deepened. The innovation practice ability of the students is improved. And the construction of the first-class course of mechanical design is accelerated.