The Electrostatic Discharge (ESD) is the main cause of some disasters in the mining environments. The ESD depends mainly on the capacitance and resistance of human-body and the capacitance is very sensitive to the environments. In this paper, the figure capacitance of human-body in mining tunnel environment was studied with numerical simulation. It was found that the human-body capacitance in mining tunnel environment depended mainly on the human figure and the shape of the tunnel, only slightly related to the position. The results implied the ESD model was significant in the mining environments; moreover, the human-body capacitance in mining tunnel environment was also approximately linear to the figure size and its value was around 250 pF, which was coincident with Human Body Model (HBM); The figure capacitance was dependent on the constituent of coal layer as well, the typical value of capacitance was 20% larger than that at free space, which meant the mining tunnel was an electrostatic sensitive environment.