Transfer function of intra-body communication (IBC) helps the understanding of signal transmission mechanism and hints for efficient communication system design. In this paper, transfer function with phase information based on quasi-static electromagnetic (EM) field modeling for a galvanic-type IBC limb is briefly reviewed. Then the compensation factor, which is calculated by the minimum mean square error (MMSE) method, is introduced to correct the inevitable deviation in actual shapes of human limb and electrical properties of tissues. To verify the effectiveness of correction factor, the square wave response is calculated and experimentally measured. Eventually, our results demonstrate good agreement between theoretical calculation and experimental measurement.