In the forward simulation of 3D magnetotelluric using integral equation method, the Cole-Cole model is led into for studing characteristics of the induced polarization effect. For the first time the authors calculate the responses of 3D magnetotelluric in homogeneous half-space including a polarizable body, and summarize some response rules. The results show that the induced polarization effect makes the value of apparent resistivity decrease. The induced polarization effect of high-resistivity polarizable body is stronger then one of low-resistivity polarizable body,especially the body with high chargeability has great effection to the response, even cause false anomaly in apparent resistivity observation.