Variable step-size algorithm may along with time change the step-size parameter, increase filter’s convergence performance, but make a lot of trouble to set the parameters. In this paper, we proposed a new convergence statistic indicator and the application of variable step-size NLMS algorithm, and with the NLMS algorithm and other scholars proposed non parametric variable step-size NLMS algorithm on simulations, and then analyzes how to select the appropriate threshold of convergence statistical indicators, in order to have both fast convergence and good steady-state error.