Large differential settlement occurs on a Taiping Market near Nanjing Changfujie Subway Station foundation pit during construction of the deep foundation pit.Factors in influencing the differential settlement of building according as several main construction stages,base of building,and soil condition are analyzed based on the measured data and software Plaxis 2D.The results show that the north building is too old and base of building has a lower sustainability,which make major differential settlement occur on the building.Therefore,the solution to problem is to rise axial force again and increase density of steel brace.