Abstract: In view of problem of bigger output ripper existed in intrinsically safe power supply based on single-phase synchronous boost technology, the paper proposed a design scheme of intrinsically safe power supply based on two-phase synchronous boost technology whose output end is added filtering inductances and capacitances. Taking the minimum kindling curve as foundation, it analyzed intrinsically safe performance and made optimal design for circuit parameters of the power supply. The sparking test proved feasibility of design of the power supply.