For a sixarm hydraulic umbrella drill,its energy loss is big.To solve the problem, a loadsensitive hydraulic system was designed,and its AMESim simulation model was established. The system's sensitiveness to load and speed control properties were validated by simulation. The simulation results show that in the loadsensitive hydraulic circuit, the flow is relative to the opening amount of the control valve; when multiple loads work simultaneously, the system keeps the pressure and flow that have been set by the loadsensitive valve. In conclusion, hydraulic parameters in this design are accurate and the design is validated by the simulation model.