In order to study the influence of subway foundation pit on the displacement of surrounding strata under the condition of dewatering. Based on the finite element modeling of a subway foundation pit project under construction in Nanjing, this paper discusses the influence of excavation only on the ground settlement around the subway foundation pit and the influence of dewatering foundation pit on the ground settlement around the subway foundation pit. Through the comparison of the two cases, the influence law of the horizontal and vertical displacement of the surrounding strata caused by the precipitation is analyzed. It is concluded that the vertical displacement of the surrounding strata caused by the foundation pit is larger in the case of the dewatering, and only the horizontal displacement of the excavation foundation pit is considered to be smaller.