Intra-body　communication　(IBC)　utilizes　the　human　body　as　the　data　channel　to　ensure　the　signal　transmits　through　the　on-body　and　implanted　sensors.　It　offers　a　low　power,　low　radiation　and　high　transmission　quality　method　for　currently　fast　developing　Body　Area　Network　(BAN).　In　our　previous　work,　the　theory　model　and　simulation　of　the　physical　model　have　been　researched.　In　order　to　design　and　implement　the　IBC　system,　the　channel　model　should　be　investigated.　In　this　paper,　a　channel　model　of　the　IBC　was　constituted,　including　the　signal　generator,　modulator-demodulator,　human　channel　with　AWGN　noise　and　equalizer　module.　Then,　in　order　to　attain　the　attenuation　properties　of　the　human　channel,　the　in　vivo　experiments　with　7　volunteers　were　carried　out　through　the　signal　analyzer　with　trace　generator　and　the　differential　probe.　Due　to　the　frequency-dependence　of　human　channel　attenuation,　the　equalizer　was　designed　to　compensate　frequency　distortion.　The　effect　of　the　equalizer　was　approximated　to　the　amplifier,　filter　and　reshape　in　the　communication　system.　At　last　the　constellations　diagrams　of　PSK,　BER　versus　SNR　of　intra-body　communication　system　were　investigated.　The　results　showed　that　the　human　body　has　a　stable　propagation　characteristic　in　the　frequency　range　from　10　kHz　to　500　kHz　with　different　volunteers.　The　constellation　diagrams　with　the　equalizer　were　much　better　than　the　situations　without　the　equalizer.　It　indicated　that　the　ISI　(inter-symbol　interference)　induced　by　the　frequency　distortion　of　human　channel　was　effectively　reduced　by　the　equalizer.　FSK　can　achieve　the　lowest　BER　versus　SNR　and　it　was　the　best　modulation　for　communication　system.　QPSK　and　BPSK　had　the　similar　BER　with　SNR.　Yet　the　8PSK　was　the　worst　collection.　©　Springer　International　Publishing　Switzerland　2014.