In foundation pit engineering within soft soil regions, suspended water-stop curtains are commonly implemented to effectively isolate the aquifer and control groundwater seepage. To mitigate fluctuations in the surrounding groundwater levels, reinjection techniques are concurrently applied, thereby establishing an integrated dewatering and recharge construction strategy. However, in practical engineering applications, the performance of such a system is subject to multiple influencing factors. This study utilizes the Visual MODFLOW finite difference software to construct a three-dimensional numerical model of a deep foundation pit associated with a subway project. By systematically varying key parameters, the impact of each factor on the overall dewatering and recharge efficiency is investigated. The simulation results indicate that increasing the depth of the underground continuous wall significantly enhances the recharge effectiveness. Similarly, a greater depth of depressurization wells improves the reinjection performance, although it may simultaneously reduce the dewatering efficiency within the foundation pit. The insertion depth of reinjection wells exerts a notable influence on the recharge process, particularly near the toe of the diaphragm wall, where a distinct boundary effect is observed. Furthermore, increasing the number of reinjection wells contributes positively to the overall reinjection efficiency. The optimal configuration for the model developed in this study is determined as follows: the insertion depth of the diaphragm wall is set at 49 meters, that of the depressurization well is set at 42 meters, the insertion depth of the reinjection well is set at 45 meters, and the optimal number of reinjection wells is set as 13. The above are the best solutions for taking values of each influencing factor.The research findings can serve as a valuable reference for the pumping and filling design in foundation pit engineering.