Offshore filling artificial island program is adopted in the new airport project construction,whose deep water cofferdam is constructed using blasting crushing and silting method.Effective determination of the amount of explosives and explosives buried depth and other related construction parameters in deep water cofferdam treatment process is key and difficult.Taking the B27 cofferdam midpoint as the research object,this paper calculates the blasting parameters,proposes construction process,and analyses the construction effect.