Abstract: Through electro-hydraulic control，transmission of Hi-Lo powershift tractor is controlled by electronic button mounted on the main transmission without cutting off power.Speed of tractor could be increased or decreased within a certain range，so as to improve work efficiency and adaptability.Foreign development history and domestic situation of powershift tractor were discussed，application characteristics of Hi-Lo clutch of powershift tractor were analyzed，results could provide a theoretical reference for development of Hi-Lo mechanism powershift tractor.