Abstract: In view of the actual running situation on the tensile test at the finished product physical laboratory of a new modern process inspection center for iron and steel enterprises, from five aspects, such as man, machine, material, method and environment, the factors that affect the test accuracy of the physical laboratory during the whole process from receiving the tensile specimens to the test data transmission were analyzed. The results show that operators, equipments, materials, testing methods and test conditions all had different effects on the accuracy of the test results. In response to these effects, improvement suggestions were put forward to improve the accuracy of the test results.