Abstarct: Understanding the fluid flow behavior of rock masses is of great importance in engineering activities such as dam, hydrocarbon extraction and storage, geothermal and nuclear waste storage. One of the most important factors affecting hydraulic behavior of rock mass is its discontinuity. The present study investigates the hydro-mechanical behavior of fractures by conducting fluid flow tests in parallel with confining stresses in natural limestone fractures. Three behavioral patterns of linear relationship, conventional nonlinear relation (inertia effect) and nonlinear relation due to fracture dilation were observed in the experimental results. At low levels of lateral stress and low flow rates, the fluid behavior is linear. At higher stresses and flow rates, the flow pattern is determined by the fracture geometry (Aperture and roughness). In laboratory results, it can be observed that for a sample with the smallest Aperture opening and the roughest fracture surface the nonlinear flow behavior pattern is due to dilation, whereas the conventional nonlinear flow occurs if the crack opening is large. The results of the two-way coefficients of Forchmeier and Izbach were calculated using statistical fit. Both of these relationships describe nonlinear behavior well, but the coefficients of the Forchmeier equation are more sensitive to stress change. The critical Reynolds number was calculated for the laboratory results. This number decreases as the confining stress ratio decreases, indicating earlier initiation of nonlinear behavior in confining stress rock samples. The coefficient of friction for fluid flow in a fracture is defined as a function of Reynolds number and relative fracture roughness. Comparison of the results of the experiment with the presented relationships shows that the proposed relation to the previous relationships yields a better estimate of the coefficient of friction. Using Fluent software, a reference model of laboratory results was developed to aid in further studies on the behavior of fractures in fluid. This software well models the nonlinear behavior of fluid flow. The results of water pressure test at Bakhtiari Dam were used to study the fluid behavior on a larger scale than the laboratory scale. The three behavioral patterns observed in the laboratory results can also be seen in the in situ test results. The critical Reynolds number for fluid flow in rock mass was also investigated. The critical Reynolds. Finally, using numerical modeling, the behavior of the coupled hydro-mechanical effect of jointed rock mass has been investigated. First, using 3DEC software and baxsed on data obtained from DFN field harvesting for rock mass and permeability status and The rock mass drainage rate is analyzed and modeled to estimate the baxse reagent volume element (REV) under hydro-mechanical coupling behavior. The values of permeability obtained in the coupling and uncoupled conditions were also compared. The modeling results show that, it is impossible to control leakage without the construction of a water curtain system.