Abstract: In order to study the influence of different redundant ways on dual protection circuit of intrinsically safe power, based on a new type of intercepting protection circuit, the contrast experiment was carried out for dual series and parallel connection respectively under the premise of simulating same fault. The results showed that when the protection circuit had the same structure, the dual series and parallel redundant protection circuit produced different protection effect due to the different fault types. Concretely, the fault I made series redundant protection circuit mistakenly closed, causing power supply stop; the fault II made parallel redundant protection cannot be normally closed, leading to security risks. Since different types of faults occurred randomly, when a single fault occurred, the series redundant dual protection circuit was more secure and reliable than the parallel redundancy ones, it was more suitable for intrinsically safe power working in explosive gas environment.