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Traditional tractors have caused great problems in resources and environment. It is an urgent task to carry out the research of pure electric tractors. The electric drive system is the core of pure electric tractor. According to the tractor’s working characteristics and transmission characteristics, a tractor electric drive system was designed based on hilly and mountainous area. It included the determination of electric drive transmission scheme, matching of driving motor parameters, design of characteristic parameters of the transmission mechanism and the power output mechanism, etc. And the Romax design analysis and strength checking of the transmission mechanism were also carried out. The fatigue design requirements met the analysis of bending stress, torque stress and damage degree of the axis. Finally, the system was tested for the external characteristics, transmission efficiency, noise and reliability on the electrically driven towing test bench built. The test results showed that the electric drive system can satisfy the characteristic requirements of the tractor tillage working condition, and it verified the rationality of the design of electric drive system. The transmission efficiency was 72%~94% under the low-running conditions of 1000r/min or less, the output torque can be stabilized;in the range of 1000~3000r/min, the output power can be stabilized to meet the tractor’s requirements under the cultivating conditions and transport conditions, which was better than that of the traditional fuel tractor. It proved that the electric drive system designed met the requirements. The electric drive system design laid a solid foundation for the development of subsequent electric tractors.