Abstract: Taking Dexing Copper Mine 4# tailings pond which is largest in Asia as an example,consider the common problems(longterm accuracy of data,reliability of system operation and realtime effectiveness of early warning) of the online monitoring system of large tailings ponds built by the midline method,a new framework for online monitoring of tailings ponds of "three systemstwo platformsone team" was proposed. Applying highreliability ubiquitous information acquisition system,highreliability Mesh communication system and distributed intelligent photovoltaic power supply system,a safety monitoring and analysis cloud service platform is constructed,which provides effective guarantee for the safe operation of tailings ponds. After more than three years of operation and improvement,the online monitoring system is reliable,realizing timely warning during the flood season,and achieving the expected results. It provides a reference for the construction of the online monitoring system of the same type of tailings pond.