The existing anti explosion measures and the intrinsic safety evaluation methods have become the bottleneck factors that restrict the further improvement of the output power of the native security. Therefore, This article is based on the latest anti explosion standard, the principle of realizing high power output by Power-i technology to suppress the spark discharge energy of switching power supply is analyzed, as well as the composition of the power supply system and its evaluation method. The forward converter is selected as the topology of the high-power local security power supply, according to the technical index of Power-i system, the circuit structure of high power intrinsic safe converter is put forward, and the double protection circuit of overcurrent, overvoltage and short circuit when the output is short circuited and open fault is designed. It has been tested that the output 24V/2A high power intrinsically safe positive converter based on Power-i standard can meet the requirements of explosion protection under type I environment. The experimental results verify the intrinsic safety of the designed high power intrinsic positive shock converter, and reflect the correctness of the theoretical analysis and design method.