In order to solve the problem that it is difficult to filter motion interference in electrocardio（ ECG）signal monitoring system

an digital self-adaptive variable step-size least mean square（ LMS） algorithm which is easy for hardware implementation is proposed. By simplifying the relationship between step-size factors and input signals

the algorithm reduces the computation of the weight updating system. Through analyzing unstablie convergence of traditional LMS algorithm

combined with iteration numbers to optimize the step-size factor

improve the convergence performance of the algorithm. Compared with the classical LMS algorithm

with computation slightly increased

convergence performance of the algorithm is greatly improved and the SNR is increased by more than 14 d B.Simulation results show that the algorithm has the advantages of small amount of computation and good to filter effect

while ECG sigal carry out realtime hardware integrated to filter motion interfernce.