The invention discloses a method for calculating the deformation of a rough dislocation crack under stress by using an experimental means. The method comprises the following steps: processing the shale of a target reservoir into a cuboid rock sample; splitting the cuboid rock sample into two rock plates with rough surfaces; staggerly placing the rough surfaces of the two rock plates to form a dislocation crack; modeling the morphological deformation of the dislocation crack under stress in virtue of inverse calculation thinking; applying given displacement onto a crack surface a plurality of times and calculating the stress on the crack under the condition of given displacement; and finally, drawing a stress-displacement plate so as to obtain the relation curve of stress and displacement.The method utilizes reliable principles, can realize analysis and calculation of the dislocation crack, and provides a theoretical basis for prediction of the deformation of downhole cracks.