The present invention relates to a compound of the following formula (I) or a pharmaceutically acceptable salt thereof, wherein R 1 and R 2 are independently H; R 3 is selected from H, a C 1 -C 7 straight-chain, and a branched or cyclic alkyl; and R 4 , R 5 , R 6 , R 7 , and R 8 are each independently selected from C 1 -C 7 alkyl, halo C 1 -C 7 alkyl and the like. The present invention also relates to a method for preparing the compound, pharmaceutical compositions comprising the compound or pharmaceutically acceptable salts thereof, and uses of the compound or pharmaceutically acceptable salt thereof in the preparation of a medicine for inhibiting HIF prolyl hydroxylase or a medicine for promoting the generation of endogenous EPO.