A kind of wireless monitoring interface device based on wireless sensor networks for ammeters was proposed. Ammeters connected by UART or pulse interface to get ammeters’ real-time data. Then, an ammeter monitoring system based on wireless sensor networks (AMSBW) was designed. The system consist building-WSN and community wireless monitoring center. And user’s ammeters, ammeter wireless monitoring interface devices and building-sink nodes were included in the building-WSN; the center sink node and monitoring host were contained in community monitoring center. The functions of real-time monitoring, remote control and preventing electricity-stolen were designed in the AMSBW which had simple installation and configuration. Then a software system to test the AMSBW was exploited. At last, system’s tests results show that it could effectively achieve the goal of real-time monitoring and control ammeter.