Asymmetry,irregularity,many buildings(structures) to be protected around,and the difficulty to topple in a direction constitute the complex environment for the demolition of a building(named Pacific Tower) with “L” shape in north-south direction.To ensure the successful collapse of the building and effectively control the harmful effects of blasting,the pre-demolition method of mechanical cutting partition and the method of increasing the incision height were adopted.Pacific Tower adopted the plan of one-time blasting demolition,which includes the combination of in-hole/out-hole delays and zonal sequential directional collapse.In pre-demolition,the building was divided into rectangular and special-shaped areas by mechanical cutting partition method.The rectangular blasting incisions were distributed in the 1st ~ 3rd floors,and the special-shaped blasting incisions in the 1st~3rd and the 8th~9th floors.In addition,the powder factors were 1.67 kg/m3 and 1.6 kg/m3 for the stand column and the shear wall,respectively.The blast holes were arranged in one row.And they were initiated in sequence by long-delay nonel detonators in the holes and short-delay nonel detonators out of the holes.The rectangular area was oriented to the southwest,while the special-shaped area was oriented to the west with three-layer folding blasting,with a delay interval of 1900 ms between the two areas.There were several measures proposed to control the damage effect of blasting.Firstly,cover protection was adopted at the position of incisions.Secondly,a 6 m high buffer layer made by waste residue was put in the collapse position of the building.Thirdly,double layer shelving was set up for passive protection for the key areas.The building collapsed successfully and fully disintegrated.Now that flying rocks,air shock wave and blasting vibrations were all within the safe ranges,and the surrounding environment was not affected,good blasting effect was obtained.