When the subway construction runs through a karst aquifer, it always causes the change of groundwater seepage field, resulting in engineering and geological problems. In order to protect the groundwater environment, a simple and safe diversion scheme is urgently needed. Based on the summary of the lithological structure and hydrogeological characteristics of the area studied, a numerical simulation method is used to simulate the change of groundwater seepage field before and after the construction of the subway stations, as well as after the implementation of diversion measures, so as to investigate the influence of subway construction on groundwater seepage field under different hydrogeological conditions and to testify the remediation effect of diversion measures. The results show that the subway station structure can be divided into three categories, namely, the double-layer seepage structure with gravel-magmatic rock pores-fissures in the soil layer(station A), the seepage structure with gravel-limestone pores-karst in the soil layer(station B) and the single-layer pore seepage structure with thick gravel in the soil layer(station C). The influence of subway foundation pit construction on the hydrodynamic conditions of the surrounding original seepage field is closely related to stratum structure. The construction of the subway station leads to the rising of the water level on the upstream face and the falling of the water level on the downstream face, the maximum backwater height of the upstream face of station A, station B and station C is 0.40, 0.32 and 0.62 m, respectively. The influence range of groundwater flow field is closely related to geological conditions, the number of stations and the angle between the directions of station construction and water flow. Generally speaking, the influence range of the upstream face is larger than that of the downstream face. Diversion measures can restore the groundwater seepage field to the greatest extent, and the Euclidean closeness between the fallen-back water level and the natural water level at each station is greater than 0.98. However, the number and location of diversion measures are affected by multiple factors such as water flow angle, geological structure, hydrodynamic conditions and so on, which should be considered according to the actual situation. The research results can provide a scientific reference for the harmonious coexistence of subway engineering construction and groundwater environmental protection.