Abstract: According to the working mechanism of combined roller, the external load torque is analyzed, and the relationship between structure parameters and load torque was studied with the combined roller of high pressure grinding mill of GM1400×800 as reference. Results indicate that the load torque of combined roller increases along with the length of match surface, the diameter of combined roller and friction coefficient. The load torque of combined roller increases linearly with the increase of magnitude of interference when magnitude of interference is small. However, the load torque of combined roller decreases when unilateral magnitude of interference is more than 0.62 mm. The load torque of combined roller presents a parabolic distribution with the increase of matching surface radius, and the load torque achieves the maximum of 10.4 MN·m when matching surface radius is 410 mm.