Analyzing and calculating the operation status of the power system with assistance of the software PSD-BPA helps a lot in the planning and operation of the power system. In view of the inconvenience of manually editing the BPA data Cards and the information islanding the BPA has,this paper proposes an interface method to establish the BPA double-way data by table mapping. This method takes consideration of the characteristics of the data model between the BPA software and other software of the power system,and realizes the interface with the database technology. Based on this method,the double-way data interface is added on the OPF software so that the OPF software can read and write BPA files freely. Finally,the reactive power optimization calculation is conducted on the operation of a certain power grid,and the optimization results in the BPA data format are generated and calibrated by BPA. The results indicate that the data interface and optimization software are effective and with good robust.