A spring，used in pylon shaft of an aircraft, has strict form and position tolerance requirement to its ends. The principle of EDM technique,spring characteristics and machinability were studied in combination of EDM machine structure and functions.A research was explored in spring ends machining by using EDM process with NC technique.Machining methods, measures to be taken and ways for problem solution were proposed. The application result show that EDM can effectively be used to solve the distortion occurred in spring ends machining，by which a stabile and reliable process in the high precision spring ends manufacture is possible to guarantee. Now this technique is successfully applied in the manufacturing of many kinds of high precision springs.It can fully meet the customer requirement with ideal result，and it has great value for application.