The traditional oil tractor has problems with high energy consumption and considerable gas pollution during operation. To ensure power and endurance, it has better economy to install the range extension scheme on the tractor. Based on the existing research results, the working mode, power system design, and energy management strategy of extended-range tractors are reviewed, and the characteristics of existing extended-range tractors are analyzed. On this basis, this type of tractor's shortcomings and future research directions are pointed out.