Abstract: With the continuous improvement of marine environmental protection requirements, a large amount of real-time online monitoring systems for flow into the sea are being or going to be build.In order to avoid blind construction, systematic and standardized design schemes are urgently needed as a guideline.For this problem, this paper comes up with a systematic and standardized design scheme for real-time online monitoring system of rivers flow into the sea in China.The designing principle, composition and individual function, operational process, data flow and so on are required in the design scheme.This scheme is implemented and the real-time online monitoring system is under long-term operation in Liao River online monitoring operation demonstration station.