Abstract: This paper presents the equivalent circuit model and a new design method for multi-layer circular polarizer. This new method is to solve the equivalent circuit model directly. As a result, the admittances are solved. According to the admittances, electromagnetic simulation software is used to determine the structure parameters of each layer metal grid plate. Based on the method introduced in the paper, three kinds of conventional circular polarizer which are two layers、three layers and four layers circular polarizers are analyzed and designed. The design results and simulation results are presented. As we can see, the simulation results agree well with the design results. The new design method has distinct advantages such as clear principle,simple design procedure and excellent design results.