This study aims to make the cable force distribution of arch bridges reasonable in the bridge state and then the overall stress state of the arch bridge structure good. With the help of the improved particle swarm algorithm, the bending moment and axial force of the main arch ring are constrained according to the principle of minimum strain energy and the influence matrix method. For the cable force optimization of arch bridges, the objective function is obtained, and the model is established. A domestic reinforced concrete arch bridge is taken as an engineering example. MATLAB and finite element software ANSYS are used to optimize the cable force of the bridge, and the optimized cable force is compared with those obtained by other methods. The research shows that in terms of global optimization capability, the improved particle swarm algorithm outperforms the standard particle swarm algorithm. The improved particle swarm algorithm can effectively avoid the drawbacks of being easily trapped in local optima and premature convergence that exist in the standard particle swarm algorithm and has improvement in the convergence speed and convergence accuracy in the iterative process. Compared with the traditional unknown load coefficient method and the minimum bending energy method, the improved particle swarm algorithm makes the cable force distribution of arch bridges more reasonable, decreases the peak value of the cable force significantly, and reduces the fluctuation amplitude between cable forces.