Abstract: great challenges to data collection in the process of safety hazard early warning. Therefore，a safety hazard early warning technology for railway large machinery operations based on the Internet of Things (IoT) is proposed. An IoT-based safety hazard early warning architecture is constructed. In this architecture，the perception layer deploys various sensor nodes scientifically through a wireless sensor network node layout module，and uploads the collected data to the data layer via the transmission layer；the data layer preprocesses the safety hazard data of railway large machinery operations；the application layer conducts in-depth analysis and evaluation of the preprocessed safety hazard data through a parameter evaluation module. In this way，the safety hazard early warning for railway large machinery operations is realized. Experimental results show that this method can effectively collect multi-dimensional data during railway large machinery operations，accurately issue warning signals，and has high accuracy and reliability in practical applications.