Abstract: In order to meet the design requirements of safety strength and lightweight of tractor cab frame assembly, the finite element analysis method was used to optimize the weight reduction design of the cab frame structure.Based on the static load test results of the original cab, the mathematical model of the lightweight frame was established.The finite element analysis software was used to simulate the strength of agricultural and forestry tractor protective device under four working conditions of static load test, and the weak structure was optimized and strengthened by secondary iteration.Finally, the cab skeleton assembly lost about 20% of its weight, passed the static load test of agricultural and forestry tractor protective device smoothly, and has been mass-produced and put into the market.