Abstract: The underground water-sealed caverns are mainly built in the crystalline rock mass in China, where water-sealing condition is very complicated considering the heterogeneous anisotropic spatial distribution of fractures in the rock mass. As the core constitution of underground water-sealed cavern, water curtain system directly concerns the water-sealed tightness. Considering the influence of geologic body anisotropy, it is necessary to evaluate hydraulic transmission efficiency between water curtain network and surrounding rock, namely, test water curtain boreholes efficiency. In the previous studies, the geological conditions are usually simplified as isotropic mediums, while geological body anisotropy are discussed in the laboratory scale in some references, which engineering applicability is general. This paper analyzes the influence of the rock mass anisotropy on hydraulic transmission efficiency in the site scale and proposes the optimization method of water curtain system considering this effect. It introduces the concept of water curtain efficiency with the lights of engineering experience. The multi-joint water curtain borehole test method is used for water curtain borehole efficiency testing in an underground water-sealed storage cavern project in Yantai. Then the water curtain system network is optimized with adding another boreholes according to experimental results. The results are obtained with threshold method which satisfies the air-tightness require under the condition of geological anisotropy. Practice proves that this method is more suitable for practical engineering and it can enhance the hydraulic transmission capacity of water curtain system significantly in the anisotropic field.