Abstract: Voltage flicker is a serious problem for electric power quality, and the higher\|order cumulant RLS algorithm based on variable forgetting factor is introduced in this paper as effective approach for tracking the voltage flicker envelope. With the improved RLS algorithm, the error criterion based on conventional mean\|squared\|error(MSE) is replaced by the higher\|order cumulant MSE criterion, which makes the algorithm not influence by the Gaussian noise. The application of variable forgetting factor (VFF) not only can improve the speed of algorithm to track the variation of envelope, but also assure better convergence performance under steady state. Simulations by Matlab shows that the proposed algorithm has better estimation accuracy compared with that of the conventional RLS algorithm under the disturbing of gaussian noise, and can detect voltage flicker envelope accurately.