To achieve high quality electromagnetic mechanism design, this paper analyzes the characteristic of magnetic circuit of solenoid valve electromagnetic mechanism, and proposes an electromagnetic mechanism design method based on working air gap (WAG) analysis. And a critical phenomenon of ampere turns is analyzed in design process. According to the requirements of output force and response time, a new structure of a magnetic circuit of solenoid valve is designed. A finite element model (FEM) is established and the prototype is test, the design has been verified.

Working air gap，Topological analysis of magnetic circuit，Electromagnetic force calculation model，Electromagnetic mechanism design