The invention discloses an NB-IoT protocol-based structure online 
monitoring system, which comprises a sensor module, a sensor collection and 
processing module, an NB-IoT data communication module, a power supply charging and power 
supply management module, a 
server side and a 
client terminal, and is characterized in that the sensor module obtains data through measurement, the sensor collection and 
processing module receives the data and sends the data to the NB-IoT data communication module; the NB-IoT data communication module is arranged at the front end, the 
server side is arranged at the rear end, the sensor collection 
processing module remotely transmits data to the 
server side through the NB-IoT data communication module, the power supply charging and power 
supply management module provides power supply, and online 
monitoring data display, storage and analysis management 
software is arranged at the 
server side. the 
monitoring data are displayed in a classified manner and stored as required, and 
online analysis is performed in real time, and early warning information is given. According to the invention, wiring is not needed, the cost is reduced, the 
power consumption is smaller, the telecom operator-level 
service quality can be provided, and the method can be conveniently applied to a complex structure monitoring environment.