Aiming at the vibration problem caused by rotor mass unbalance of large hydropower unit, a method for analysis and processing based on dynamic load balance to establish centrifugal force equation was proposed.Firstly, a large number of field test sample data and the regression analysis method were used to modify the traditional empirical trial counterweight formula, obtain the accurate regression coefficient and determine the trial counterweight’s mass.Then, the trial counterweight was added on the rotor, the varying rotating speed measuring results before and after adding the trial counterweight were compared to find balance points of the same vibration under different rotating speeds, and establish the centrifugal force equation.Finally, the centrifugal force equation was solved to obtain the total dynamic unbalance mass.Taking a certain hydropower unit as an example, the effectiveness of the proposed method was verified with tests.The results showed that compared with the traditional method, the proposed method can deal with the dynamic balance problem quickly and effectively.