Abstract: The real-time flood control hydrological information transmission system in the Huaihe River Basin was built by a public packet switching data network which is a new technology, and has been supplied by post and teleco mmunication bureau recently and widely appliced abroad as a communication medium.The application of this system has changed the long-time lagging situation of transmitting the real-time flood control hydrological information by using lowspeed telex and has produced obviously social and economical benefits.This paper fully introduces the system's backg round, communication channels, constructions, functions, hardware conbination, software development, running situatio n and benefits.