It is impossible to quantitatively analyze the pore connectivity and fluid seepage path, and a seepage experiment of an intact rock sample cannot provide information about the strength, deformation, and seepage of rock samples with different fracture forms. In recent years, with the rapid development of computer computing performance, the numerical simulation method for rock permeability has been done more often. The most commonly used numerical simulation methods include the finite element, discrete element, and finite-discrete mixed models [PERSON] et al. (2013); [PERSON] et al. (2013). In the finite software, during the process of deformation, the material points of the study area still maintain the adjacent relationship of the shape and are unable to simulate the fracture and separation process of the block. The continuous method has difficulty presenting the microscopic and macroscopic crack morphologies, and the seepage process of the fluid is simulated by giving the block water mechanical parameters [PERSON] et al. (2010). Compared with the finite element method, the discrete element and hybrid methods can simulate the movement and separation of the block. In the discrete element method (DEM), the rock is simulated by the joint between the polygon block and the block. The polygon block cannot be destroyed. The fissures are generated along the edge of the polygon, and the initiation, expansion, and closure of joints between polygonal blocks can simulate the formation of fractures in rock by simulating the responses of microscopic and macroscopic cracks under stress load. The fluid cannot pass through the block, and the fluid flow process can be simulated by giving hydraulic parameters to the joints [PERSON] et al. (2013); [PERSON] et al. (2013). Because of the complex morphology and uneven distribution of the pore structure, researchers have selected fracture models to carry out seepage experiments. The influence of the macroscopic crack angle and crack model on the seepage characteristics has not been addressed in the literature. In fact, different crack angles and different fracture modes of rock samples have great influences on the seepage flow. In order to deepen the understanding of the permeability law of different fracture modes under unloading action, this paper considered the intrinsic advantages of DEM in simulating fracture seepage. The Udec polygon method was used to study the seepage characteristics of sandstone without filling fissure. The crack reconstruction technique, based on the fracture feature of experimental rock samples, was used to establish two kinds of stress-water coupling numerical models: (1) the variable-angle single-crack model and (2) the typical fracture model based on the fracture characteristics of a rock sample. The established models were used to study the variation in the hydraulic aperture of microcracks and macroscopic cracks in an unloading environment as well as the morphology of the main seepage passages. The seepage characteristics of different angle cracks under different unloading stress paths were explored, and the laws of seepage variation of different crack forms under different stress environments were analyzed.