Abstract: A methanesulfonate polymorph of a 5-type phosphodiesterase inhibitor. The structure of the 5-type phosphodiesterase inhibitor is as shown in formula A: The methanesulfonate polymorph of the 5-type phosphodiesterase inhibitor includes the following diffraction peaks measured at 2? reflection angles in an X-ray powder diffraction pattern: 7.1750°±0.2°, 7.6299°±0.2°, 8.8588°±0.2°, 13.2310°±0.2°, 14.3754°±0.2°, 14.8440±0.2°, 15.2941°±0.2°, 17.1838°±0.2°, 20.0314°±0.2°, 20.8507°±0.2°, 21.2839°±0.2°, 21.7890°±0.2°, 22.2594°±0.2°, 23.0373±0.2°, 25.1243°±0.2°, 25.4244°±0.2°, 26.1530°±0.2°, 28.1210°±0.2°, 30.0135°±0.2°, 31.4809°±0.2°, 32.3619°±0.2°, 37.2410°±0.2°, 37.6388°±0.2° and 40.8286°±0.2°. The methanesulfonate of the 5-type phosphodiesterase inhibitor not only improves the activity of drugs, but also improves the water solubility and the bioavailability of the drugs, and makes up the blank of studies on drugs of the crystal form.