The torque shaft of the shearer cutting part can not only transfer torque, but also protect the cutting motor in special cases. Taking the MG500 / 1140-GWD shearer in Malan Mine as an example, the depth, width and distance between the unloading groove and the end are taken as the optimization objects. Based on the orthogonal test method, 25 groups of optimization schemes are designed, and the Abaqus software is used to model and analyze the optimization scheme. The results show that the unloading groove of torque shaft does appear very obvious stress concentration phenomenon, which is much larger than the stress value of other parts. When the width, depth and distance between the unloading groove and the end are 9 mm, 3 mm and 320 mm respectively, the maximum stress value of the unloading groove is 541.98 MPa, which is slightly larger than the allowable shear stress value of the material 540 MPa, indicating that the optimization scheme can meet the actual needs of the torque shaft and is the optimal solution.