Implantable bioelectronics are becoming more widespread for biomedical applications. To avoid frequent surgical operations, self-powered implantable bioelectronics are more attractive. Traditional wireless power transfer (WPT) methods suffer from limitations that include bulky size, short transfer distance or flexibility limitation. In this paper, we present a new body channel based wireless power transfer (BC-WPT) method which uses the human body as power transfer medium to transfer power. In this way, the power transmitter and power receiver don't need a transmitting coil/antenna and a receiving coil/antenna. BC-WPT has the advantages of lower size, long transfer distance, and flexibility.