The invention provides a sewage treatment monitoring system based on an internet of things. The sewage treatment monitoring system based on the internet of things is simple in structure, low in cost and easy to install and maintain, and comprises a water quality sensor, field control equipment, a heterogeneous data receiver, a PLC / DCS controller, an ad-hoc network wireless node, a wired / wireless redundancy ring network, an operator station, a chart printer, an industrial Ethernet, an NOM server and a mobile client terminal. The sewage treatment monitoring system based on the internet of things can be compatible with multi-network protocol conversion, monitors various water quality sensors and control devices in real time through a wired / wires redundancy ring network node, performs analysis, early warning and precise control on the phenomena of equipment failures, excessive energy consumption, abnormal water quality and the like through cloud computing and large-data mining, and avoids equipment failures, water discharge beyond standards and the other major accidents. The sewage treatment monitoring system based on the internet of things is simple in network construction, low in cost and easy to install and maintain, and has good application prospects.