Abstract: In view of the complex hardware and low reliability of the direct collection method of mine multi output intrinsic safe power supply current, an indirect collection method of intrinsic safe current is proposed. Through the comparison and analysis of the structure block diagram of two intrinsic safe current acquisition methods, it is concluded that the indirect acquisition method of intrinsic safe current has the characteristics of simple circuit and high reliability. This paper introduces the hardware circuit of indirect collection method of intrinsic safety current, the software calculation method and program flow chart based on piecewise linear interpolation. The results show that the error of indirect collection method of intrinsic safety current is small, which can meet the needs of field use of coal mine.