Disclosed are a rough surface fissure generation method based on digital image technology, and an experimental system, relating to the technical field of rock mechanics experiments. The method comprises the steps of: A. loading a rock specimen with a through fissure formed therein, and removing debris on the surface of the specimen; B. a scanner scanning a rough fissure surface to obtain a digital image of the rough fissure surface; C. processing the digital image, wherein denoising processing and threshold segmentation processing are involved; D. performing normalization processing on an RGB value of the digital image to obtain a normalized matrix, establishing a space coordinate system, and obtaining a restoration scale of an image digital matrix; E. calculating a digital restoration matrix; and F. completing simulation of a rough surface fissure, and restoring a complete space fissure. The experimental system for the method comprises: a housing (1), a column (2), a telescopic cylinder array (3), a control system (4) and a hydraulic circuit (5). By means of the method and system, the roughness structure of a rock fissure can be accurately described, thereby facilitating the study of the laws of the physical mechanics of rock rough fissure seepage.