Abstract
The topic of this graduation project is the theoretical research and design of the hydraulic-control valve. The point is to expatiate on the operation principle and function and type and use situation of overflow valve and pressure-reducing valve as well as sequence valve. And depend on CAD to design the hydraulic-control valve. The point is overflow valve, in order to make its static and dynamic characteristics of the relief valve better and get reasonable economic achievement .In the graduation project, the detailed drawing of overflow valve has been drawn by AutoCAD in order to make project convenient .