Design a kind of reducer, the first stage transmission is a cylindrical cam, the secondary stage transmission is a gear transmission. Multistage transmission of the reducer has carried on the design calculation and checking. On the basis of the lateral cylindrical cam lateral transmission mathematical model, conducted the spiral curve analysis and calculation with numerical analysis software MATLAB. Import the spiral curve data into SOLIDWORKS to complete the 3D modeling of cylindrical cam. According to the structural design of cylindrical cam, complete reducer machine design and virtual assembly of gearless reducer. The stress analysis was carried out on the cam disk with the ANSYS Mechanical Analysis Module of SOLIDWORKS, designed to meet the working conditions. Conducted physical development based on CAD and CAE. The result showed that the design was fast and effective, significantly shorten the production cycle.