A specialized and distributed DCS third party interface software was developed base on the semAPI protocol and INICI12 module communication interface components supplied by ABB Symphony DCS system, expounded to illustrate the actual usage of the DCS communication interface in the power plant. Development of the distributed DCS third party interface software was run in WindowsNT/2000operating system, the server/client system structure. Server was connected in the factory LAN or independent in the network, take the responsibility of data collection, saving and transmission, and other functions, client through the network to read in the production process server real-time data, completed user defined software kinds of data label point function.