Aiming at the problems of wire resistance interference and distorted measurement results in high-temperature strain measurement using long-wire strain gauges, this paper presents a high-temperature strain correction method based on the data collected by the strain indicator and the measured resistances of the strain gauge and its lead wires. By correcting the tested strain and resistance parameters, the real strain values of the strain gauge under high-temperature environments are obtained, and then the thermal output curves and sensitivity coefficients at different temperatures are determined. Finally, the accuracy and reliability of the proposed correction method are verified through practical engineering application cases. The results show that this method can effectively eliminate the measurement errors caused by long leads and high temperature, improve the precision of high-temperature strain measurement, and provide a theoretical basis and technical support for structural strain testing in high-temperature environments.