The deformation of deep excavation pit supported by row piles and soil nailing at Tianxi International Center of Yinchuan was simulated by using PLAXIS software. The calculation model was established by using a 15-node triangular element to simulate the soil that was divided into seven layers, and the concrete surface layer was simulated with grouting element, the row of piles was simulated with plate element and the soil nail was simulated by using the combination of point anchor and geo-grid. Calculation results showed that large deformation was found at the junction of two supporting forms, which indicated that the rigidity of the support structure had remarkable influence on the deformation of the excavation pit. The deformation of pit slope increased gradually with the increasing of excavation depth, and the final deformation at top of slope was greater than that of the bottom.Through comparison between simulation result and monitored result, some common laws of foundation pit deformation were concluded.