In order to meet the monitoring requirements of three-way load of a certain aircraft landing gear, a landing gear load test method was proposed based on fiber Bragg grating (FBG) sensing and multiple linear regression. The strain distribution of the landing gear under different loads was obtained with finite element analysis software. According to the characteristics of strain distribution, the position of the FBG strain sensor was determined, and the strain sensing network was formed. On this basis, the ground static load calibration experiment of the main landing gear was carried out, and the strain-load calculation equations were formed by multiple linear regression method. Finally, the load calculation equations were verified by experiments. The research results show that the method based on fiber Bragg grating can effectively back-calculate the three-way load of landing gear, and the relative error between the back-calculated load and the applied load is within 5%, which meets the actual engineering requirements.