Intra-body communication (IBC) is a short-range body based communication using the human body as the transmission medium in biomedical application. Quasi-static electric field modeling of the galvanic coupling IBC human limb channel is analyzed. Governing function can be reduced to Laplace's equation, bone and joint effects are considered as the boundary conditions. Analytical solutions of voltage distribution in the human limb from the model are obtained. Effects of human limb's properties in the model are studied. Finally, in vivo validation and calculation results are presented. Especially, the gain is greatly affected by the ratio of the thickness of muscle and bone both in calculation result and in vivo experiment. © 2011 IEEE.