The problem of identifying the rigid axis of resonator in HRG is discussed. In this paper, a method for identifying the rigid axis of hemispherical resonator based on amplitude frequency characteritics is proposed. Firstly, starting from the dimensional mass vibrations model of hemispherical resonator the expression of amplitude frequency respons characteritics is derived. Secondly, the response of the resonator in different excitation directions is simulated, and the feature selction method of rigid axis is determined. Thirdly, the excitation responses under defferent frequency splitting and defferent Q values are simulated, and the applicable conditions of rigid axis of hemispherical resonator identification method are proposed. Lastly, the principle and method of rigid axis identification proposed in this paper are verified by experiments. The rigid axis identification of hemispherical resonator with a frequency splitting value of 0.3 Hz、0.18 Hz、0.01 Hz is carried out. The correctness of the identification principle and method is verfied. The principle of this method is clear, the identification device is easy to realize, and the operation efficiency is high, which provides an effective way for the subsequent process of resonator quality leveling engineering.