The design and construction of directional blasting demolition of a 120m high chimney in Changzhou is introduced, where existing hot gas pipeline, workshop, communication tower and high voltage line and so on. The environment of blasting area is complex and near to the protection objects, it is difficult to control the collapse vibration and flyrocks. According to the features of chimney structure and the site actual situation, good blasting results are achieved by rising the blasting cut height, selecting reasonable design scheme and parameters and adopting pertinence safety precautions measures of damping ditch, damping earth embankment and cut-off wall.