Abstract: Discrete time variable structure control system designed by a discrete reaching law is the definite function of the system states. It is sensitive to the system parameter variations and external disturbances. This paper proposes a novel control scheme which combines biologically inspired shunting model with the discrete sliding mode variable structure control. The proposed scheme is applied to the liquid level control system with variant parameters, which is modeled by genetic algorithm. Simulation and laboratory results show that the proposed controller is superior to the conventional discrete sliding mode variable structure controller, which is more robust to system parameter variations and external disturbances and has the better static performances. The study provides a theoretical basis for improving the liquid level control performance in modernized agricultural production.