Aiming at the problem that the dynamic balance process of a flexible rotor needs to start and stop frequently to add test weight, which is time-consuming and labor-consuming, and the balance accuracy is difficult to guarantee, a dynamic balance optimization method of flexible rotor based on Grey Wolf Optimizer(GWO) is proposed. In this paper, a virtual prototype model is established based on a power turbine rotor for a certain type of turboshaft engine, and a rotor test platform is built. The transfer function is used to find the relationship between unbalance and vibration response, and the equilibrium equations are established to solve the problem. In the process of solving the problem that the equilibrium equations are mostly contradictory, GWO is used to solve the contradictory equations to obtain the optimal counterweight scheme at the full working speed of the rotor. The results show that the method proposed in this paper eliminates the tedious test weight process of traditional dynamic balance, and the vibration reduction effect is better than the conventional on-site dynamic balance. The work of this paper can improve the efficiency and accuracy of flexible rotor dynamic balance and provide technical reference for the vibration control of aero-engine.