In view of the relatively few researches on the chassis layout of electric tractor, the chassis layout design was carried out based on the matching results of the whole machine. The model was established by using 3D modeling software, and the center of gravity parameters of main parts of whole machine was extracted. Then, by analyzing the mechanical characteristics of tractor traction unit, a mathematical model was established. Taking the traction efficiency of the electric tractor and weight of the whole machine as the optimization objective, the NSGA-Ⅱ algorithm was used for multi-objective optimization. The influence factors of tractor’s stability, driving force, load fluctuation and life of drive system and walking system parts were considered as the constraint conditions of the algorithm. The constraint equations were set up. The gravity function of the electric tractor, centroid of front and rear battery packs and centroid of the whole machine were taken as the target variables, and the objective function of optimal power and economy was derived. Through the ModeFRONTIER platform, the NSGA-Ⅱalgorithm was used to optimize the battery distribution. The results of the optimization under two different tillage depth conditions were compared and analyzed. It was found that when the tillage depth was 180mm, the overall weight of the optimized electric tractor was reduced by 14.3% compared with the weight of experience method, and the counterweight was only 25.3kg. When the tillage depth was 240mm, the overall weight of the electric tractor was reduced by 10.3% compared with the weight of experience method, and the counterweight was only 4.4kg. The results showed that the empirical method based on traditional tractor was not suitable for electric tractors. Under the working conditions, the driving wheel slip ratio of the optimized electric tractor was less than the characteristic slip ratio, and the traction efficiency of the whole machine was obviously improved.