To study the influence of seepage field on the freezing temperature in the loose accumulation rock group of the intake air shaft in the gold mining area in the northern sea area of Sanshan Island, Laizhou City, based on the flow velocity measurement and the material parameters of the rock group, the COMSOL finite element numerical model was established. The intersection time of the three-circle freezing construction of the vertical shaft and the formation time of the freezing curtain were predicted, and the reliability of the design and numerical simulation of the three-circle freezing construction scheme of the vertical shaft was verified by an engineering example. The results show that due to the high flow velocity of coastal groundwater, the intersection line of the inflow surface is shaped like teeth during the freezing process. The low temperature of the freezing pipe has a significant impact on the downstream under the seepage action, and the freezing curtain develops asymmetrically and shifts to the downstream of seepage. The three-circle freezing design reduces the temperature of the shaft excavation area to below the phase transition temperature of −1 ℃ after 18 days of freezing. In the engineering verification, the intersection time and the freezing curtain formation time are 25 d and 36 d, respectively, which are consistent with the numerical simulation results. The research results can provide reference for similar projects.