The hemispherical resonator gyro is the only vibratory gyro that can reach the accuracy of inertial navigation. The vibrational state of its resonator may change under the influence of external environmental conditions, making the output signal of gyro unstable. In order to study the sensitivity of the hemispherical resonator gyro to the gravity fields in different directions, the mechanism of HRG’s signal output change caused by gravity field is analyzed. The dynamic simulation analysis of resonator in two dimensions of structure stiffness and anchor loss is carried out by using the finite element method(FEM), and corresponding tests are carried out to verify the analysis results. The results indicate that the gravity fields in different directions have no obvious effect on the performance of hemispherical resonator gyro.