We have analyzed the interaction between lightwave and microwave in polymeric electrooptic modulators. Local poling structure was suggested to apply to the waveguide modulators, which will enhance the interaction between lightwave and microwave and improve the modulation efficiency considerably. In addition, instead of the coplanar electrode, the microstrip line was proposed to be the modulating electrode. Slotline, used as the ground electrode, will make the performance of the device adjustable and compensated by application of different substrates. The parameters used for optimization of the device then increase. At last, the influence of geometric parameters on the overlap integral between light wave and microwave was shown.