Abstract: The electrical apparatus used in the gas transmission and distribution station shall meet the requirements for antiexplosion. Intrinsically safe electrical apparatus is the best choice against explosion. With the power supply device as object of the intrinsically safe electrical apparatus study, using the precise time-varying model for power and circuit, and combining the experiment waveform, this paper has studied the features of sectional discharge of electrical induction as well as the relations between ignition capability of sectional sparks and circuit parameters in details. Based on the theory of Minimum Ignition Energy and in an aim to meet the requirements for intrinsic safety and electrical performance, an optimization and designing approach for electrical induction and capacity parameters is proposed. Through analysis of numerical simulation, the range to select the optimized parameters has been worked out. The experimental results indicate that, as for the circuit after parameter optimization, it meets the requirements for intrinsic safety, and also meets the requirements for electrical performance, since the input ripple voltage is only 1.25% of input voltage. It is a feasible approach for parameter optimization and can greatly enhance the safety performance of electrical apparatus.