Abstract: For the control problem of discrete-time systems with noise disturbance and uncertain parameters,a strong tracking filter is used to estimate uncertain parameters firstly,and then a sliding mode control method based on discrete adaptive reaching law is proposed.The chattering problem is studied and analyzed deeply for the discrete-time reaching law,and a new sliding mode controller based on the new reaching law is designed.Simulation results demonstrate that the designed controller can effectively reduce chattering and improve the control performance.