Human body potential caused by walking on floors has been modeled by a RC equivalent circuit. Based on the measurement of the charging voltage by human body walking, the RC equivalent model has been deduced and the influence of the parameters on the human bod voltage has also been analyzed. The human body equivalent circuit corresponds with the RC network. As a consequence, an exponential function can be obtained to describe the walking voltage. The model of human body voltage charging by walking combines two main processes: an exponential increase of human body potential due to charging by the soles repeatedly detaching from the floor during walking, and for discharging, the human body potential has an exponential retention. The time constant is determined as a series combination of body resistance and capacitance relative to the ground. During the walking process, the periodic changes of walking paces cause the periodic changes of the body capacitance to ground, then the human walking voltage can be determined by the capacitance. The walking voltage modeled has reached agreement with experimental data.