Abstract: Take the variation law of internal force and deformation of mixed-supporting system for research target, base on some deep foundation pit dug by Open Cut Method, by the method of field monitoring, the displacement、anchor stress、supporting axial force of the supporting structure and some problems occurred during the construction are analyzed.The main conclusions in this thesis have been summarized as follows: a) the displacement of pile top and pile body reached to the maximum when dug to the bottom of foundation pit.The maximum displacement occurred at the position of 6m-upper part of foundation pile;b) With the excavation of foundation pit, the cable stress rise in wave-like change, the temperature and construction loads is the reason for cable stress showed wavy change;c) the displacement、anchor stress、supporting axial force of envelope have obvious synchronization with the depth of excavation, monitoring data is stable overall, the mixed-supporting structure for the deep foundation pit is secure.