In order to study the evolution law of the fracture morphology of rock under impact disturbance, this study carried out five sets of strain rate impact experiments on red sandstone through the Split Hopkinson Pressure Bar system, and calculated the absorbed energy. The fracture section was scanned by 3D contour scanner, and three roughness parameters were extracted to analyze the correlation between energy dissipation and fracture section morphology. The results show that there is a critical strain rate of 107.2 s−1. When the strain rate is lower than this value, the section is flat and the roughness parameter increases slowly. When the strain rate is higher than this value, the section shows a step-like large height difference morphology, and the roughness parameter increases rapidly. The absorbed energy and the roughness of the fracture section increase monotonically with the strain rate, and the variation trends of the three roughness parameters are consistent, which confirms that the roughness of the fracture section is a multi-dimensional synchronization process driven by energy dissipation. This study provides a basis for the stability prediction, impact energy inversion and support parameter optimization in mining engineering.