The artificial ground freezing (AGF) method is an advanced construction technology in line with green building and sustainable development. It has been more and more widely used in municipal engineering with the rapid development of urban construction in China. However, with the increase in the scale and quantity of AGF projects, engineering accidents have also shown an increasing trend in recent years. The research which based on the case investigation of accidents in recent decades and the latest modern risk management and control theory in China systematic identification of risk sources in AGF projects from the five aspects of worker, equipment, method, environment, and management. Finally, it established a dynamic risk assessment method that considers the freezing pipe quality, the seepage velocity, and the freezing effect before excavation. In the end, based on the new method, the risk source identification and dynamic risk assessment about the cross-passage freezing project in Beijing were carried out, and the evaluation results could better reflect the actual situation.