Abstract: The additional vertical water curtain system is required in the underground water-sealed oil storage cavern project in coastal areas to meet its water-sealed properties and control seawater intrusion. In order to study the design method and parameters for the vertical water curtain system, the influence laws of four parameters of hole distance from the storage cavern (d), hole spacing (b), hole length (l) and hole injection pressure ( p_\texti ) of the vertical water curtain on the groundwater seepage field, water-sealed properties, water inflow and seawater distribution range around the cavern are obtained by using the finite element numerical simulation method and compared with the existing results for verification based on an underground water-sealed oil storage cavern in the coastal area. The research shows that the hole distance of the vertical water curtain from the storage cavern mainly has an impact on its burial depth range. The range of influences of the length depends on the location of the change beyond the storage cavern, and the spacing and injection pressure affect the entire depth range. The degree of influences of the four parameters on the water-sealed properties and prevention of seawater intrusion are as follows: b<l<d< p_\texti and d<b<l< p_\texti , respectively. A total of seven cases in the study are at risk of seawater intrusion into the cavern, and further enhancement of freshwater recharge is required. The research results can provide a theoretical basis for the design parameters of the vertical water curtains of the groundwater-sealed oil cave reservoirs in coastal areas.