Abstract: Aiming at present situation that height adjustment of cutting platform in silage harvester mainly depended on driver′s manual control of hydraulic oil circuit and visual experience，a control device with fixed height for header was designed. Angle sensor was used to obtain height information of cutter.According to requirements of operation，height of cutter can be adjusted intelligently with one key.A reliable and detailed control process was developed through field test and combining with actual requirements of users.The device had simple structure and safe control process.And it can effectively reduce workload of operator，reduce labor intensity and improve operation efficiency of silage harvester.