Abstract: In order to improve product reliability and environmental adaptability, it is necessary to improve friction characteristics at -50℃ of interior orientation motor assembly in an electro-optical pod. Possible factors influencing friction characteristics of motor assembly are analysed, and corresponding improvement measures for these factors are put forward. Effectiveness of the improvement measures are verified with combination of simulation and experiment. Results show that at -50℃, increasing friction torque is both the result of the role of low temperature alone, and the results of low temperature and potential factors of motor assembly together. The micro deformation of motor assembly at low temperature is not sufficient to cause the increasing of friction torque. The friction torque of the motor can reduce to 0.063 N·m by adding a protective cover of the motor and a soft magnetic alloy sheet with a thickness of 1 mm between motor and motor seat. These improvements apply to the design of motor assembly of electro-optical pod and research of similar products.