The reliability and service life of the heavy-duty and high-speed gear transmission system are severely affected by the large impact load of the system. The objective of this study is to reduce the impact load of the cutting transmission system by optimizing the motion parameters during the operation of the shearer. Taking a coal mining machine gear transmission system as an example, an electromechanical coupling model of the power transmission system of the shearer including the dynamic model of the motor and the dynamic model of the coupled gear train and the planetary gear train was established. The simulation results show that under sudden load changes, the dynamic optimization of the motion parameters reduces the impact load in the cutting transmission system. An experimental bench for the cutting power transmission system was set up to study the effects of motion parameter optimization on the impact load of the cutting transmission system. The trend of the impact load of the transmission system and the speed adjustment duration obtained from experiments and simulations are in good agreement, verifying the effectiveness of the motion parameter optimization.