The mass unbalancing is one of the main defects in the manufacturing process of the hemispherical resonator, which has important impact on the vibration performance. To formulate the evaluation method of resonance mass unbalance and provide the basis for balancing, the structural characteristics and mass unbalance of the resonator are characterized. Through the coupled vibration physical model and simulation analysis, the mechanism of the coupled vibration of the resonator and the influence of the mass unbalance on the frequency splitting and support loss are clarified. Through experiments, the frequency splitting characteristic and coupling vibration characteristics of the resonator under different removal masses are measured, and the relationship between the mass unbalance of the resonator and the vibration characteristics is obtained. The distribution characteristics of the 1st, the 3rd and the 2nd harmonics of the resonator without balance and the support loss introduced by them are 1. 6×10 -8 and 3. 7×10 -9 . The corresponding relationship between frequency splitting and 4th harmonic unbalance mass is 0. 01 Hz/ μg. Therefore, the mass unbalance of the resonator can be evaluated and the balancing process is formulated.