In view of the signal detection and classification of power quality disturbance problem，the power quality disturbances detection and classification methods based on EMD were proposed, and the common several kinds of disturbance signal were simulated. The time of disturbance occurrence and duration, the frequency and amplitude of disturbance can be detected accurately by this method. Such as voltage sags, voltage swells, voltage interruptions and other disturbances raised the signal amplitude and frequency changes can be estimated. The results of MATLAB simulation show that the proposed method is simple and effective. 