In order to apply the IEC60870-5-104 telecontrol protocol，an Ethernet protocol for monitoring and controlling the substations or equipment in wide area to the field of industrial communication，this study analysed the structure of the IEC60870-5-104 telecontrol protocol，and presented a method for design and development of a PLC communication module based on this protocol. The hardware platform of this communication module mainly includes the processer based on the AＲM7 kernel and Ethernet controller. The software platform uses the embedded real-time multi-task operating system to schedule the tasks of configuration file read，state feedback，module and PLC controller information exchange，data transformation according to the protocol request. The consistency，interoperability and system performance of the module were tested by experiments. The results showed that the communication module had the characteristics of independence，stability，strong interoperability，high reliability and so on.