The invention discloses a method, device and system for detecting a strain crack of a coating material, and a medium. The method for detecting the strain crack of the coating material comprises the steps of acquiring strain detection data of the coating material when being stretched or compressed; generating a strain change curve according to the strain detection data; analyzing the strain changeof the coating material according to the strain change curve; and judging the state of the strain crack of the coating material according to the strain change. According to the method, device and system for detecting the strain crack of the coating material provided by the invention, the state of the strain crack can be judged, and the data support is provided for analyzing the damage mechanism ofthe coating material.