The present invention relates to a class of phenylpyrimidone compounds, the pharmaceutical composition, the preparation method and the use thereof. More specifically, the present invention relates to a type of phenylpyrimidone compounds of the following formula I, the pharmaceutically acceptable salts or solvates thereof and to the pharmaceutical composition as well as the preparation method of the said compounds. The said compounds of formula I according to the present invention can effectively inhibit type V phosphodiesterase (PDE5), and thus can be used for the treatment of various vascular disorders, such as male erectile dysfunction, pulmonary hypertension and the like.
