In　recent　years,　wireless　sensor　networks　have　been　widely　used　in　monitoring　the　operational　status　of　power　systems　and　other　industrial　production　activities.　The　traditional　battery　power　supply　method　has　the　disadvantages　of　high　pollution,　limited　effective　power　supply　lifespan,　and　the　difficulty　of　replacing　batteries.　The　piezoelectric　energy　harvesting　method,　which　converts　the　mechanical　vibration　energy　into　electrical　energy,　has　become　a　current　research　favorite.　In　this　paper,　a　self-powered　improved　double　intermediate　diodes　and　capacitors　(DIDC)　interface　circuit　is　designed.　Firstly,　theoretical　analyses　of　improved　DIDC　interface　circuit　and　some　common　interface　circuits　are　provided.　Then,　the　energy　harvesting　power　and　output　voltage　of　different　interface　circuits　in　different　load　resistances　are　simulated　and　compared　using　Multisim　software.　The　results　show　that　the　improved　DIDC　interface　circuit　has　higher　output　power,　output　voltage　and　good　load　adaptability,　which　makes　it　a　better　prospect　for　engineering　applications.