A drainage network sedimentation management method based on a large Internet of Things (IoT) model is provided. The method includes: acquiring flow data of a pipe section; determining a flow cross-sectional area series of a plurality of adjacent pipe sections based on the flow data of the pipe section; determining a target detection area and a target detection time based on the flow cross-sectional area series of the plurality of adjacent pipe sections; controlling a robot to perform sonar detection on the target detection area at the target detection time, and acquiring sonar detection data; determining a sedimentation risk based on the sonar detection data and pipe characteristics; automatically generating a desilting path and desilting parameters based on the sedimentation risk; controlling automated desilting equipment to travel along the desilting path to a desilting operation point, and performing a desilting operation based on the desilting parameters.