With development of the current coupling intra-body communication research, it is necessary to increase carrier frequency of communication in the future research to obtain high-speed and stable communication mode. The feature of tissue in human limbs is intensively analyzed with the carrier frequency of 1MHz to 10MHz when the condition of quasi static approximation is tenable. In combination with relevant theories and experimental data, it is concluded that quasi-static coupling of human body is not tenable, which may be used as the theoretical basis for further research of modeling theory.