The deep excavation in a complex environment would inevitably cause soil deformations,which will induced underground foundation pit collapse accidents happening by deformation of soil. In this paper,by researching the whole process of foundation pit construction safety based on the deformation monitoring data,discusses the deformation regularity and risk level change in the development of foundation pit. Then,utilizes triangle fuzzy mathematics to establish probability interval and calculates the corresponding fuzzy probability. By means of analyzing the correlation between different monitorin...