According to GB/T 25117 and relevant standards, the traction system of rolling stock needs to carry out characteristics test, the typical torque of all speed points under 90% maximum speed corresponding to maximum torque should not less than 95% of specified value under the conditions of hot and cold motor. To ensure the torque characteristic measurement results of locomotive traction system accurately and reliably, the measurement model was established and used to analyze uncertainty sources combining with real experiment system. Measurement results of torque characteristics in different curves were evaluated, and the results showed that the methods and instruments were effective and reliable. This method provided the technical basis for the reliability of the measurement results of rolling stock traction system torque characteristics.