In this paper,integrating the principium of demolition blasting of buildings and the practice,the general mechanism and affection factors of blasting harms such as blasting shock,collapsing shock,blasting rock,blasting shock wave and blasting noises produced in demolition blasting of buildings are analyzed.The safety problems existed in demolition blasting of buildings are discussed from three aspects such as the unsafe behavior of "person",the unsafe state of "substance"and the unsafe condition of "environment".Based on an engineering example,the difficulty of safety blasting of engineering example was analyzed,on this basis,corresponding effective safety defending measures and the method of safety control are brought forward.This study is significant to the construction safety and control of demolition blasting of similarity tower building in practice.