In the motor design,the estimation value of the contact resistance has a great influence on the correct calculation of the motors stall torque.However,at present,the contact resistance value depends on the designers experience.And the contact resistance changes with the change of the structure and state of the motor.Therefore,it is difficult to calculate the contact resistance.A measurement method of contact resistance was proposed.Firstly,the curves of contact resistance changing with different speeds of the experimental motor and the curves of contact resistance changing with different torsional spring forces were measured.Then the curves were fitted by power functions.The experimental results show that,with the increase of the current,the contact resistance value decreases rapidly at the beginning and then decreases gradually until it becomes stable.By the fitted contact resistance,the simulated stall torque is close to the measured stall torque.