Aiming at the problem of signal distortion, nonideal denoising,and poor reconfiguration in the denoising method for power quality signal based on wavelet threshold, an improved denoising method for power quality signal based on the theory of compressed sensing(CS) is presented.CS denoising method mapsthe signal into a lowdimensional space firstly.Considering the characteristicthat the power quality signal can be represented sparsely and reconstructed while noise signal can’t berepresented sparsely.Then the original signal can be reconstructed with orthogonal matching pursuit algorithm (OMP),and the purpose of denoising is finally achieved.The simulation shows that the CS denoising method is superior to the traditional threshold denoising method based on wavelet denoising,and signal is not distortion.And the proposed method is easy to realize since it completes denoising at the same time of signal collection and compress, and provides a new method for the power quality signal denoising.