A compound of 5-hydroxyl-1,7-naphthyridine substituted by aryloxy or heteroaryloxy, a preparation method thereof and a pharmaceutical use thereof are provided. In particular, the compound has the following Formula (I), wherein R2 and R3 are each independently H R1 is H or C1-C3 alkyl Ar is an aromatic ring or a heteroaromatic ring selected from a naphthalene ring, a pyridine ring, a thiophene ring, a furan ring and a substituted benzene ring. Pharmaceutically acceptable salts of the present compound, are provided, as well as uses of the compound or pharmaceutically acceptable salts thereof in the preparation of a medicine for inhibiting HIF prolyl hydroxylase or a medicine for promoting the generation of endogenous EPO.