The invention discloses an OPC-based interface method for realizing system communication of two different types of protocols. The method comprises steps that, a software dog starts for starting and monitoring an OMT interface software main program; a configuration file is loaded; connection between an MODBUS TCP client and communication stations of other protocol systems and an OPC server is established; a thread is developed to establish MODBUS monitoring service, a request message from the MODBUS TCP client is analyzed to acquire communication data, and the data is stored in a common variable area preset by a main program; after the main program is successfully connected with the OPC server, two threads are simultaneously developed for the OPC server for data writing and reading. Compared with the prior art, system data interaction of the two different types of protocols can be realized, the OPC technology is utilized in the data interaction process as a bridge, the data interaction technology blank of the system of the MODBUS TCP client and other protocol systems is filled, characteristics of the OPC technology are utilized, and standardized software interface communication is realized.