Various types of hydraulic valves are used to control hydraulic equipment including construction equipment such as excavator, crane. etc. The main control valve is a core component, to complex control fluid flow or supplying constant fluid pressure to actuator in accordance operating environment. Excessive flow rate is drained for safety of hydraulic system by main control valve. In this study, the scheme program to change the boundary condition according to behavior of the spool valve is developed. Using this results, the CFD analysis are accomplished.