Abstarct: Many of the dams' reservoirs have leakage problems that may occur due to the foundation or dam body. Among the measures taken to prevent this phenomenon underwater structures is the installation of sealing curtains. By means of a suitable injection pattern, these sealants can be effective against water escape. The study is to determine the injectable pattern for strengthening the Tangab dam construction site. In the first step, field studies from the dam site that is including the perceived discontinuities (orientation, aperture, continuity, etc.) and then the data collected by DIPS and EASY-FIT software were analyzed and evaluated, and the statistical distribution functions dominated by the discontinuity characteristics were obtained. In the second step, a discrete fracture network (DFN) was constructed baxsed on the data in the software in 3D in the discrete software of 3DEC. In the third stage of the tensor, the permeability of the dam site is obtained by numerical method and is compared with and validated by the leak tolerance values by the Luzhan test at the Tangab dam site. In the fourth step, in order to obtain the release of injected materials, the modeling performed the injection operation in several steps with increasing injection pressure finally, according to the site of the dam, with the maximum permissible injection pressure, which is less than the loading pressure the most appropriate release was obtained at a pressure of 25 bar with a distance of 1.5 m in the injection borehole, which caused the boreholes to coincide and can be provided as an appropriate injection pattern for water sealing in the water escape route.