In order to comprehend the influence of rotary tiller group on the vibration characteristics of tractor seat in transport and working state, the vibration model of the tractor system with 3 freedom degrees were established in the vertical plane. The vibration simulation of Dongfanghong MG654 tractor suspened 2BYL-4 rapeseed rototiller system was carried out with Matlab/SIMULINK to obtain the minimum air spring pressure value and the current value of Mr Damper when the root mean square of seat weighted acceleration was the smallest. The simulation results show that the smallest value of the seat weighted acceleration root mean square is 0.629 m/s2 when the air pressure is 5 bar and the current is 0.650 A in transport state, and the smallest value of the seat weighted acceleration root mean square is 0.520 m/s2 when the air pressure is 5 bar and the current is 0.250 A in working state. It shows that the root mean square value of the acceleration of the seat could be reduced by changing the air pressure of the seat air spring and the current of the Mr Damper, thus the driver’s driving experience could be effectively improved. The experimental study was carried out when the seat weighted acceleration root-mean-square value was the lowest, and the seat nonlinear vibration test results were compared with the simulation results, and the maximum relative error was 6.40%. It can be seen that the established nonlinear model is reasonable.