Abstract: Rescue borehole probe adopts usually wellhead wired power supply. In this paper, according to the requirements of mining intrinsically safe design, distributional inductance and the influence of capacitance on the intrinsic safe performance were analyzed, the relationship among the power of the rescue probe, twisted-pair transmission line length and wellhead supply voltage was given. With the impact factor of two models, the selection method of parameters such as wellhead power voltage, power supply distance and probe power was given in the actual design.