1-[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazol[4,3-d] pyridin-5-yl)-4-ethoxybenzene sulfonyl]-cis-3,5-lupetazin citrate or Aildenafil citrate crystal form O and the preparation method thereof are provided. The pharmaceutical compositions containing Aildenafil citrate crystal form O and the use thereof in preparing the drugs for treating male erectile dysfunction (ED) are also provided. The crystal form O can be prepared by the steps of: dissolving the raw material, Aildenafil citrate, in the mixed solution of distillation water and tetrahydrofuran, stirring, raising temperature, filtering, stirring filtrate, reducing temperature, holding temperature, crystallizing, filtering, and so on. Drugs can be prepared from the crystal form O together with the pharmaceutically acceptable excipients, and then used in treating male sexual dysfunction disease.
