Aiming at achieving reliable communication between the underlying device and the monitoring center, a new application layer protocol based on TCP is designed to deal with the huge amounts of data transmissions and high real-time requirements of some data. The protocol proposes secure login method from the acquisition device to the remote monitoring center, and it can complete transmitting real-timely specific parameters and components according to the actual requirements. The protocol has great flexibility, scalability and security, which can meet the demand of data transmission between the acquisition device and the monitoring center in the monitoring system of large facility.