By transforming the operation control system of transmission, the automatic control for the traditional mechanical transmission could be realized. Three types（electronically controlled hydraulic, electronically controlled pneumatic, electronically controlled electric）operation control system was compared，superiority of the electronically controlled hydraulic operation control system was summarized，the working and structure principle of the electronically controlled hydraulic operation control system was explained, the control system of the intellectual shift was introduced. The system has not been generally applied in tractors at present，and it is worth popularizing.