Intra-body　communication　(IBC)　is　a　novel　transmitting　technique　suitable　for　wearable　and　implantable　sensors　in　home　health　care　systems.　Utilizing　the　conductive　property　of　human　body,　IBC　employs　human　body　as　the　medium　for　transmitting　electrical　signals.　As　a　result,　electromagnetic　interference　can　be　greatly　reduced　for　devices　communicated　within　human　body.　These　advantages　are　significant　for　the　instance　of　long　term　physiologic　parameters　monitoring　and　elder　patients.　However,　most　of　the　researches　pay　attention　to　the　experiments　and　simulations　of　IBC.　In　order　to　understand　the　mechanism　of　the　IBC　deeply,　a　multilayer　cylindrical　volume　conductor　model　of　human　forearm　is　developed　analytically　in　this　paper.　The　simplified　model　provides　the　information　of　transmitting　electrical　signal　through　human　body　and　forms　a　basis　for　developing　IBC　applications.　As　the　first　step　of　this　research,　the　quasi-static　approximation　is　assumed　because　the　transmission　is　operated　in　a　low　frequency.　Then　the　potential　and　current　density　distribution　within　the　multilayer　model　is　depicted.　Also　the　attenuation　of　human　data　channel　is　discussed.　Finally,　several　optimized　conditions　for　galvanic　coupling　IBC　are　proposed.　©2009　IEEE.