The invention discloses a method for predicting the initial flow conductivity of a rough crack. The method comprises the following steps of (A) brining rough surfaces of two rock plates of the same size into contact to form a sample plate with a rough crack in the middle, and measuring the height h of the sample plate; (B) scanning the two rough surfaces of the crack in the step (A) using a three-dimensional laser scanner and obtaining three-dimensional data of the rough surfaces; (C) calculating opening degrees W(x, y) at different positions using the height h of the sample plate in the step (A) and the three-dimensional data obtained in the step (B); (D) calculating the average opening degree Wof the crack using the W(x, y) obtained in the step (C); (E) calculating the fractal dimension D of the opening degree of the crack using a cubic covering method according to the W(x, y) obtained in the step (C); and (F) calculating the initial flow conductivity F of the rough crack using the W and D which are obtained in the steps (D)and (E). The invention has the advantages of reliable principle and simple operation, can provide a basis for optimization of fracturing construction parameters, and has a broad market prospect.