The invention discloses a construction site safety risk identification, assessment and prevention method comprising the following steps: S1, creating a real-time model of a construction project, identifying and assessing a dangerous work area in the real-time model, and creating a DVF; and S2, acquiring real-time data of a construction site, detecting the safety risk of the construction site according to the real-time data and the DVF, generating a warning, and perfecting safety precautions. Through the method, the construction process of a dynamic project can be visualized in real time, unknown risks can be identified and assessed, safety precautions can be strengthened, and the safety of the construction site can be improved. A BIM semi-finished product model can be created with the project advances. Risks can be identified in phases, and the accuracy is higher. The safety risk of a construction site can be identified, assessed and prevented in real time. The working state of workers can be monitored in real time. Once there is a worker approaching a danger area, the alarm is raised immediately. The precaution consciousness of workers is improved. A real-time and effective building construction safety management system is formed.