The dq transform is a common method to detect transient power quality, but the accuracy of the method will be greatly affected in the case of complex disturbance. For this problem, the method based on dq transform and wavelet-multiresolution analysis is put forward. Through the wavelet-multiresolution analysis, the low frequency of the signal is separated, then instantaneous dq transform is made on the isolated low frequency components. At the same time, the electromagnetic transient disturbance is separated by the morphological filter, so the interaction between different disturbances is avoided. Finally, the proposed method and the conventional dq transform method are simulated and compared with Matlab/Simulink software. The results show that the proposed method has strong anti-interference ability and excellent comprehensive performance.