Two structures of the multilayer polymer electro-optic modulator based on coplanar waveguide（CPW）have been proposed including the compensation layer structure and the shield layer structure.The results of characteristic parameters of the CPW modulator have been calculated by conforming mapping method.Compared with the typical modulator,the compensation layer structure can reduce the effective refraction difference between the optical wave and the microwave,moreover,the shield layer structure can not only reduce the effective refraction difference between the optical wave and the microwave,but also can eliminate the effective refraction difference by optimizing the structure parameters.That makes it possible to achieve velocity matching and impedance matching at the same time.