Abstract
This paper introduces the research background of 200/60t-20m bridge crane's main hoisting reducer, as well as it's research significance and research actuality of domestic and overseas. Through a detailed analysis on the referenced literature, I expatiated the concept of lifting cylinder with three-tier column helical gear's transmission, including the transmission's design, main strength and other contents as well; In the technical route, I discussed the choice on the form of gear's transmission structure , the choice of the basic parameters , the calculation of the size , the strength emendation of several major accessories and so on. Besides, I also introduced the method of using the Matlab to optimize the reducer's volume and weight so as to make this design more suitable for the social production..