Trade unions are committed to safeguarding the legitimate rights and interests of employees. The supervision of employee work safety can urge enterprises to implement safety measures, ensure that employees work in a safe environment, and reduce accident injuries. By inspecting and resolving safety hazards reported by employees in the workplace, the incidence of accidents can be reduced. The current way for union workers to check safety hazards is not real time, and related problems cannot be reflected in union staff in a timely and rapid manner, resulting in the low work efficiency of union staff. To solve the problems existing in the current way of workers checking safety hazards, this study developed a “Check, Protect and Promote” mobile supervision platform based on big data technology. The “Check, Protect and Promote” mobile supervision platform is an important means for union staff to solve safety hazards reported by employees. The platform integrates and processes the data uploaded by employees, uses big data technology to analyze the data, and finally, provides feedback on the problems so that union staff can promptly, clearly and quickly address safety hazards found in the workplace. It is an online smart platform. Existing safety hazards can be divided into several major categories. Employees who report problems can report them according to the response category, and the platform will also handle them according to the different problem categories. With the help of big data technology, the union supervision platform can speed up the resolution of problems reported by employees in real time through data integration, statistics, processing and analysis. In the future, the development of this mobile supervision platform can be widely used in the union system.