Abstract: Based on cylinder model human body bio-impedance is analyzed, transmission property of channel in-body isdiscussed. In frequency range of (3-5)GHz human body has a good response to transmitting signal. For communication on-bodybinary phase switch keying(BPSK), considering power consumption and bit error rate(BER) of channel, has better performancethan other modulation for wireless body area network(WBAN)..