Disclosed are selective phosphodiesterase inhibitor compounds shown in formula (I) or (II) for treating Erectile Dysfunction, the pharmaceutically acceptable salts and configurational isomers thereof. In the formula, the substituents R1, R2, R3, R4 and R5 are defined as in the specification. Also disclosed are methods for preparing same, and a medical composition comprising compounds of formula (I) or (II), and the use of these compounds for preparing a drug treating or preventing male Erectile Dysfunction.
