Abstract: Requirements of ia grade explosion-proof type of gas drainage pipeline equipment were analyzed, and realization scheme of ia grade pipeline equipment was gave from aspects of parallel pressure limiting circuit, series current limiting circuit and isolating circuit. In view of equipments connection of power supply circuit and signal transmission link in gas drainage monitoring system, design schemes of power supply circuit with ia grade, substation level equipment with ib/ia conversion and adding ib/ia converter were proposed. The field application verifies reliability of the schemes.