The type of cylindrical index cam mechanism with different size roller is proposed on the basic of original cylindrical mechanism. Using the elastic deformation of small roller pin to constraint mechanism of axial vibration may occur. The small roller pin mechanics analysis model is established,by changing different parameters to analyze the deformation of the pin roller and to determine the deformation of pin roller on a certain condition. By the work above,the parameter table is obtained and the basis for accurate modeling and dynamics analysis in the future is provided.