Abstract: With the gear is widely used in precision transmission and other fields, in order to meet the needs of various fields, the kinds of gear are increasing, the precision requirements are improving, and the hob needs to meet the needs of gear processing. There are a lot of interrelated parameters in the hob and the calculation is large, so the design process of the hob is more complicated and difficult, and it is difficult to meet the requirements of the production cycle and accuracy of the hob with the conventional design method. So this paper company in cylindrical spur involute gear hob design experience, developed a hob design based on knowledge engineering system, the system basic parameters of the gear processed by input, use of expert experience formula to calculate the related parameters of gear hob, then generate 3 D models and 2 D drawings of gear hob, reduce the workload of design personnel, The efficiency and precision of hob design are improved. The research and development of the system has great reference value for the digital design and intelligent manufacturing of cutting tools.