The invention relates to a suspender arch bridge optimization design method and system under moving load, and the method comprises the steps: S1, drawing up the size of each member of an arch bridge, and building a finite element model; s2, on the basis of linear static force calculation, a finished bridge suspender force is obtained and serves as an initial optimization value of the finished bridge suspender force; s3, on the basis of the stability and strength effect of the main arch, forming a moving load immobilization working condition, and loading the moving load according to a fixed position; s4, calculating the moving load and the initial defect based on nonlinear calculation, and iteratively optimizing the optimal suspender force; s5, completing the design of residual components according to a conventional method; the system adopts the methods of S1 to S5; according to the method, the strength and stability of the main arch are considered, the moving load and the initial defect are considered for iterative optimization, the better finished bridge suspender force is solved, the design result is closer to the actual situation of the bridge, the bridge safety performance is higher, the method is easy to achieve in a programmed mode, the optimization speed can be adaptively changed, and the method can be used for large-scale optimization design of the large-span arch bridge. And the economical efficiency is higher.