Voltage flicker is one of theimportant indicators of power quality,and test flicker first need to extract flicker amplitude modulator.Presents an improved TeagerKaiser energy operator method to estimate voltage flicker amplitude modulation wave,this method only needsthe three sampling points of the detection signal with simple basic operation, the process of the flicker amplitude wave extraction is fast and simple.Furthermore, to get accurate detection results under white noise, wavelet threshold denoising was applied, to eliminatethe noise ofelectrical signals. The simulation resultsprove the accuracy and validityof the proposed method. The algorithmcan overcome the influence of noise on power quality detection, has high precision, and easy to implement.