The invention discloses a dust online monitoring system, comprising a transport layer, a platform layer and an application layer, wherein the transport layer comprises a wired network, a wireless network and a 4G network; and a dust monitoring device, a noise monitoring device, a meteorological monitoring device and a video monitoring device are arranged in the application layer. Multiple environmental parameters such as the total suspended particulates, PM10, PM2.5, temperature, humidity, wind directions and wind speed are integrated according to the application layer, 24-hour online continuous monitoring is performed, and the characteristics of multi-parameter, real-time performance, intelligence and the like are achieved; data is transmitted through three major networks that are the wired network, the wireless network and the 4G network, and the real-time monitoring data can be rapidly updated; the monitoring data from different regions and different time periods is collected through the platform layer, a massive storage space is realized, the multi-dimensional and multi-spatial and temporal data statistical analysis can be performed, the administrative section can carry out thework in an orderly manner, and meanwhile, the system can accumulate data for establishing construction site environmental pollution control standards to further promote the long-term management of air pollution.