Safety risk control is the core content of project safety management. According to the characteristics and construction technology of large-area vacuum preloading engineering for soft foundation treatment of reclamation engineering, we identify the dangerous source existed in the construction process, analyze and evaluate the risk source with the LEC method, and determine the risk level of each risk source, so as to further determine the 4 major security risks: walking capacity of workers in poor areas, power line connection or breakage immersion in water, blowing sand ship encountering seasonal winds, insertion machine track foundation instability, etc. Developing special safety related control measures, and focusing on prevention and control, we prevent effectively the occurrence of the accident.