Deep geothermal reservoirs have great potential for exploitation and are characterized by high temperatures, high stress, and strong heterogeneity. However, these reservoirs contain widely and continuously distributed dominant flow channels with high permeability, predisposing these reservoirs to the formation of dominant flow, which notably decreases the efficiency of heat extraction. Focusing on the dominant flow in fractures, this study provides a definite concept, systematically reviews current studies, and puts forward suggestions for future research. It is expected that this study will serve as a reference for the sustainable, high-quality development of deep geothermal resources.