Deep foundation pit monitoring is capable of supplying essential technical support for foundation pit design and construction security. In order to study the deformation properties of supporting deep foundation pit in Donggang Business District, Dalian, combined with distributed optical fiber monitoring and conventional monitoring, excavation synchronization monitoring of foundation enclosure was carried out. The main objects to be monitored include deep horizontal displacement of supporting piles, inner support axial force and surface subsidence at the edge of the excavation. Combined on the hardening soil-small model (HSS), the finite element analysis software, Plaxis, is intended to accomplish the computational analysis, and the finite element computational results were determined in parallel comparison with the objective data of two distinct deep foundation pits. The research indicates that the rationality of the HSS model considering the small strain properties of the soil has been proved as a result of the fact that the finite element computational analysis are comparatively consistent with the measured data. And what has been validated is that the distributed optical fiber monitoring scheme also has obvious ad-vantages in data continuity and accuracy compared with conventional monitoring methods. The research results of this paper are capable of supplying a reference for the monitor of deformation and early alert of deep excavation supporting.