A compound represented by formula I: wherein, Ring A is selected from the group consisting of: pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, imidazole, pyrrole, pyrazole, triazole, tetrazole and phenyl; Ring B is pyridyl; Ring C is: a saturated monocyclic carbocycle containing from 4 to 7 ring atoms, or a saturated monocyclic or bicyclic heterocycle containing 4 to 8 ring atoms; when Ring C is a saturated monocyclic carbocycle, R 1 is hydroxyl; when Ring C is a saturated monocyclic or bicyclic heterocycle, one of the ring atoms in the saturated monocyclic or bicyclic heterocycle is an N atom, and R 1 is R 6 CO, R 6 SO 2 or R 6 SO attached to the N atom, wherein R 6 is selected from the group consisting of C 1-6 alkyl, monocyclic cycloalkyl, and trifluoromethyl; R 2 is selected from H, C 1-6 alkyl, C 1-6 alkoxyl, C 2-6 alkenyl or C 2-6 alkynyl; R 3 is at least one group attached to Ring B, which is independently selected from at least one of H, C 1-6 alkyl, halogen and C 1-6 alkoxyl; R 4 is at least one group attached to Ring A, which is independently selected from H; halogen; hydroxy; amino; cyano; C 1-6 alkyl, C 1-6 alkoxyl, C 2-6 alkenyl or C 2-6 alkynyl, optionally substituted by halogen; and monocyclic or bicyclic aryl or heteroaryl optionally substituted by halogen; X is CH, or pharmaceutically acceptable salts, stereoisomers, isotopical labels, solvates or polymorphs thereof. Ring A is selected from the group consisting of: pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, imidazole, pyrrole, pyrazole, triazole, tetrazole and phenyl; Ring B is pyridyl; Ring C is: a saturated monocyclic carbocycle containing from 4 to 7 ring atoms, or a saturated monocyclic or bicyclic heterocycle containing 4 to 8 ring atoms; when Ring C is a saturated monocyclic carbocycle, R 1 is hydroxyl; when Ring C is a saturated monocyclic or bicyclic heterocycle, one of the ring atoms in the saturated monocyclic or bicyclic heterocycle is an N atom, and R 1 is R 6 CO, R 6 SO 2 or R 6 SO attached to the N atom, wherein R 6 is selected from the group consisting of C 1-6 alkyl, monocyclic cycloalkyl, and trifluoromethyl; a saturated monocyclic carbocycle containing from 4 to 7 ring atoms, or a saturated monocyclic or bicyclic heterocycle containing 4 to 8 ring atoms; when Ring C is a saturated monocyclic carbocycle, R 1 is hydroxyl; when Ring C is a saturated monocyclic or bicyclic heterocycle, one of the ring atoms in the saturated monocyclic or bicyclic heterocycle is an N atom, and R 1 is R 6 CO, R 6 SO 2 or R 6 SO attached to the N atom, wherein R 6 is selected from the group consisting of C 1-6 alkyl, monocyclic cycloalkyl, and trifluoromethyl; R 2 is selected from H, C 1-6 alkyl, C 1-6 alkoxyl, C 2-6 alkenyl or C 2-6 alkynyl; R 3 is at least one group attached to Ring B, which is independently selected from at least one of H, C 1-6 alkyl, halogen and C 1-6 alkoxyl; R 4 is at least one group attached to Ring A, which is independently selected from H; halogen; hydroxy; amino; cyano; C 1-6 alkyl, C 1-6 alkoxyl, C 2-6 alkenyl or C 2-6 alkynyl, optionally substituted by halogen; and monocyclic or bicyclic aryl or heteroaryl optionally substituted by halogen; X is CH, or pharmaceutically acceptable salts, stereoisomers, isotopical labels, solvates or polymorphs thereof. <EOS>