The invention relates to the technical field of medicine, in particular to a quinazolinone derivative, a preparation method and application thereof. The invention discloses quinazolinone compounds as structural general formula (I) or pharmaceutically acceptable salt thereof. Most of the compounds have stronger PDE5 inhibition activity than that of Sildenafil, and have higher selectivity than thatof PDE 6 distributed on a retina. Therefore, the compounds are expected to show better clinical safety and effectiveness, and have wide clinical application prospect.