Body area network (BAN) can be used in wirelessly interconnection of the small and intelligent (bio) medic sensors attached to or implanted into the human body for medical healthcare. This paper modified the conventional model of the channel of BAN and addressed the issues for the hardware system implementation. Based on the equivalent circuit model, the influences of all equivalent capacitors are analyzed. Experiments are conducted to simulate the changes of equivalent capacitors. The relationship of channel gain and the changes of equivalent capacitors are determined. The conclusion is, in the system design of body area communication based on quasi-electrostatic field, enlarging the size of transceiver electrodes, reducing the distance between electrodes and human body, grounding the transceiver, reducing the capacitors between human body and earth could increase the receiver signal amplitude.