Abstract: The original Hanjiang cascade reservoir regulation system has the problems of decentralized functions, inconsistency in data sources and low reliability in system operation. By proposing water system reformation and upgrade project, we first sorted out and analyzed the tasks of reservoir regulation and operating requirements, and then completed the reformation designing and implementing of the system by keeping up to the pace of technical development. The new system completes the integration of system functions and data sources, integrated data presentation, steady transferring of information reporting, and duty management and flood forecast based on operation processes and precipitation. It greatly promotes efficiency of daily flood regulation, and fine management level in reservoir regulation. Furthermore, we introduced the reformation design scheme and network structure of the system, data flow, functions designing (including function structure, information collection, system processing and back-end services, information presentation and duty management, external contacts and decision support) , design difficulties and features.