Abstract: Combined with a complex environment condition of foundation pit engineering with an apartment, considering the condition including shield tunnel of metro beneath foundation pit, a simplified big well method is firstly used to calculate the hydraulic gradient curve of outer stratum of foundation pit under the dewatering condition of curtain failure(condition one), and two-dimensional finite element method is used to calculate the hydraulic gradient curve of outer stratum of foundation pit under the dewatering condition of effective curtain(condition two). Then the additional settlement of subway shield tunnel caused by dewatering of foundation pit is calculated by the layered summation method, and the influence of dewatering of foundation pit on underground subway is analyzed. The results show that:(1) Considering two dewatering conditions including the failure and effective of water proof curtain, the drawdown of the central axis on the right line of subway shield tunnel are 4.2 m and 1.5 m, respectively; (2) Considering two dewatering conditions including the failure and effective of water proof curtain, the maximum settlement of the central axis on the right line of subway shield tunnel are -2.83 mm and -1.3 mm, respectively, which meets the safety operation requirements of rail traffic.