Load calibration experiment is the key work for flight load verification and flight test of civil aircraft. The efficiency of the flight load verification is meaningfully determined by the reliability of load calibration experiment. This paper aims to theoretically and experimentally study the load calibration of civil aircraft wing with large aspect ratio and elastic beam based on the scaled model, which includes the design of fixed device for wing loading, the data processing, the basic hypothesis test, the selection of regression variables and optimisation of regression equation, etc. Firstly, the systematic error is eliminated based on the sample difference method. Then, on the basis of the multiple linear regression method, the multi-collinearity among variables is weakened by using the multi-collinearity verification technology. Subsequently, the abnormal sample points are eliminated by the means of cyclic residual analysis. Finally, the optimized variables are screened with the method of the stepwise linear regression, and the load equations for the civil aircraft wing with large aspect ratio can be established. It is demonstrated that the calculated results verifies well with the engineering requirements by comparing with experimental results, and the error is smaller than 5%.