The starting processes of main clutch and shifting clutch for planetary transmission in tracked vehicle were introduced through analyzing the traditional starting process of main clutch. Using shifting clutch as starting clutch, a method was put forward, and the control method of the starting process of shifting clutch was instituted. The joint process of starting clutch was controlled by mechanical hydraulic buffering valve. The test showed the design of shifting clutch starting is feasible, and it satisfied the demand of starting process basically. It could do much help to the realization of non-main clutch starting process control.