By using the technology for charging an electric vehicle at the same time with two charging piles, a charging pile group operation management unit is designed to control and manage multiple charging piles, which can be used for both small power single charging electric vehicle and high power double charging electric vehicle. Combined with the "Internet plus" technology, it puts forward mobile phone APP, online and offline card charging method, the three modes of payment is used at the same time. In software, modular design is used to standardize charging process, and data stream is transmitted between modules through message bus mechanism; in the double charging operation, any two of the charging piles can be combined in charging pile group, charging can be started and terminated on any pile after the combination, and the main piles and auxiliary piles are installed in the charging of double piles for management. The operation of a number of Xiamen bus station shows that the charging pile group operation management unit is stable and reliable. Compared with the traditional charging device, charging pile group operation management unit makes the charging power choices more diversified and lowers cost for the charging station design. This work is supported by National Key Research and Development Program of China (No. 2016YFB0101800).