As for a class of nonlinear discrete systems with unknown parametersa multi-model control method based on the improved BP neural network is proposed.Firstlythe nonlinear system is expressed with a linear part and a nonlinear part.When the nonlinear part has small impact on the systemthe linear robust controller designed based on the fixed model and the adaptive model is directly used to control the system.When the nonlinear part has large impact on the systemthe adaptive control under the improved BP neural network is adopted.Secondlythe switching criterion is used to smoothly switch the control input and the stability of the system is proved.Finallysimulation results show that the proposed method can improve the system control quality and reduce the oscillation of the control signal.