Abstract: Aiming at the error caused by spool dead zone and cylinder asymmetry in proportional valve-controlled asymmetric hydraulic cylinder control, a fuzzy sliding mode controller with variable dead zone compensation was designed, and the control accuracy and stability of this controller under no-load and negative load conditions were studied. The simulation results show that the sliding mode control method with variable dead-zone compensation can weaken the "flat top" phenomenon and lag caused by the dead-zone characteristics of the spool and the asymmetry of the cylinder. In no-load test, the maximum control error of general sliding mode control method with variable dead-zone compensation is ±5 mm, and that of fuzzy sliding mode control method with variable dead-zone compensation is ±2.5 mm. In the negative load test, due to adding the counterbalance valve, the shaking problem of the piston rod can be solved when it extends under the negative load of 20 kg.