The depth of foundation pit is 265m in Liyangshengjing Plaza of Shenyang, which is a super large deep foundation pit. Because of the high groundwater level and deep dewatering depth, the construction is difficult with high safety risk. This paper elaborates and analyzes the foundation pit support and excavation, dewatering and drainage, engineering monitoring and other constructin technical measures as well as the main points of construction safety management. By means of strict safety production management, the deep foundation pit construction is smoothly completed.