Abstract: In Controlled Blasting Project of large scale buildings and structures of city,the advantages of the big diameter hole drills is greatly more than the little diameter hole drills.And analyse through the contrast of demolition scheme,the speed that this method can accelerate constructing.It is the effective way of the urban project demolition.Through the design of the parameter,detonating network and the security of blasting,it has gotten the satisfactory result of demolition,and offer success experiences for blasting of similar project.