In order to carry out aircraft structural load safety monitoring and accumulate relevant structural load data for aircraft fatigue life assessment, it is necessary to establish aircraft structural load model related to flight parameters. For the nonlinear relationship between aircraft structural loads and flight parameters,the SMO algorithm with improved stopping criterion and the particle swarm optimization algorithm were used to improve the support vector machine regression method,and the flight parameters involved in the modeling were selected by the method of flight dynamics analysis combined with the Pearson correlation coefficient. The aircraft"s transonic pitch maneuver was taken as an example , and a shear force model of a certain load-bearing section structure of the wing was established. The results show that the accuracy of improved support vector machine regression method is better than the original method. It is concluded that the improved support vector machine regression method can improve the accuracy and generalization ability of the established model.