Abstract: The mechanical properties of Nb₃Sn superconducting wire were tested by Zwick Z020 electronic universal material testing machine and Zwick Laserxters 1000762 optical extensimeter. A set of high precision and high stability tensile test method at room temperature has been researched and formulated. In order to verify the feasibility and stability of the method, multiple sets of data were tested and the mean value X, the standard deviation s, the relative standard deviation COV and the relative standard uncertainty U_RSU (N) of each performance were calculated. The results show that the accuracy and stability of mechanical properties of Nb₃Sn superconductor material tested by the method were very high. The test method could provide an effective guarantee for the smooth development of high field magnets and accelerator magnets.