The operation control hydraulics are an important element of the technique. It is used in many industries, but it is problematic due to its impact on the environment. The result of the task is the design of a two stage pressure relief valve, which is useful in water hydraulics. The valve is designed for usage up to a pressure of 40 MPa and a flow rate of 50 l / min. In the design and planning we used an analytical and numerical approach. One of the important goals was that the valve was as simple as possible to manufacture. On the prototype of the valve, basic measurements were made, which showed defects due to poor quality of production. A plan was prepared to correct the error and suggestions for further work.