Calibration test is the key segment of flight load measurement by strain bridge method. In order to simulate the characteristics of aerodynamic load pressure center continuously changing with aircraft maneuvering in real flight, a load calibration test method with variable pressure center is proposed. The force balance and constraint loads of the whole aircraft are calculated and analyzed, and the multi-point coordinated loading system is applied to the wing load calibration test of an aircraft. The load model is verified by the variable pressure center loading condition, and the error caused by the pressure center change is clear. The model is optimized by adjusting the pressure center distribution of the modeling condition, and the accuracy and application scope of the load model are improved. The results show that the left wing and right wing of the longitudinal maneuvering flight load measured by the optimized load model are symmetrical, and the change of pressure center is within the verification range, so the measurement results are reasonable and reliable.