Aimed at the problems that the aircraft structure load measurement is affected by the structure temperature in the process of flight test of aircraft structure load measurement in recent years, on the basis of analyzing the cause and mechanism of thermal output of straingage bridge for load measurement, a method is proposed based on polynomial fitting for analysis and correction of thermal output of straingage bridge. This method is valid through ground temperature being tested. The method is used to correct the measurement results of several aircraft structural load flight tests, and a good correction effect is obtained, effectively improving the accuracy of load measurement. The research results provide the correction of thermal output of the straingage bridge in load measurement with an applicable theoretical basis and engineering method, and provide an important technical support for flight test and verification of aircraft structure load.