Based on standing wave precession, a quick diagnosis and compensation method for phase imbalance faults in two-axis detection loops of hemispherical resonator gyroscopes was suggested. The common phase error compensation value was obtained by observing the constant coupling of orthogonal control forces during constant-speed precession. The differential phase error compensation value was derived by analyzing the residual orthogonal control forces at varying precession rates. The mutual coupling of control forces in the detection mode was eliminated by adjusting the phase imbalance error compensation values for the demodulation quantities of the two-axis detection loops. This restored the resonator to its resonant state and reduced the peak-to-peak value of the angle-dependent bias (ADB). Experimental results showed that the ADB peak-to-peak value decreased from 15.56 (°)/h to 0.71 (°)/h, a reduction of approximately 22 times, validating the effectiveness and correctness of the proposed method.