The present application discloses an A-type polymorphic substance of yonkenafil hydrochloride and a preparation method, a composition and use thereof. The powder diffraction pattern of the A-type polymorphic substance of yonkenafil hydrochloride comprises diffraction peaks at three or more 2θ values selected from: 8.4±0.2°, 11.3±0.2°, 13.9±0.2°, 14.2±0.2°, 14.7±0.2°, 16.8±0.2°, 17.1±0.2°, 19.7±0.2°, 21.0±0.2°, 21.7±0.2°, 22.4±0.2°, 23.3±0.2°, 23.8±0.2°, 26.8±0.2°, 27.5±0.2°, 28.0±0.2°.