Home　health　care　system　and　long　term　physiologic　parameters　monitoring　system　are　important　for　elevating　the　living　quality　of　chronic　disease　patients　and　elderly.　Elaborating　towards　a　sophisticated　and　comprehensive　home　health　care　system,　Intra-Body　Communication　(IBC)　is　believed　to　have　advantages　in　power　consumption,　electromagnetic　radiation,　interference　from　external　electromagnetic　noise,　security,　and　restriction　in　spectrum　resource.　In　this　article,　we　start　from　quasi-static　Maxwell＇s　Equation　and　propose　a　mathematical　model,　which　includes　electrical　properties　and　proportion　of　human　tissues,　for　IBC　on　a　human　limb.　By　solving　the　mathematical　model　analytically　and　conducting　in-vivo　experiment,　our　model　has　shown　adequate　agreement　with　experiments.