An indolizine compound represented by formula I, a pharmaceutically acceptable salt, an enantiomer, a diastereomer, a tautomer, a solvate or a polymorph thereof, wherein, R 1 is selected from the group consisting of R 10 is selected from the group consisting of H, halogen, -NH 2, -NO 2, optionally substituted C1-C6 alkyl and optionally substituted C1-C4 alkoxy; R 2 is selected from the group consisting of H, halogen, cyano and optionally substituted C1-C6 alkyl; R 3 is R 6 and R 6' are each independently selected from the group consisting of H, methyl, ethyl, propyl and cyclopropyl, and at least one of R 6 and R 6' is H; X is an optionally substituted saturated or unsaturated 4-7 membered cyclic hydrocarbyl group or an optionally substituted 4-7 membered saturated or unsaturated heterocyclic group, and the heterocyclic group contains 1-2 heteroatoms selected from O, N, S and P; R 4 and R 5 are independently selected from the group consisting of H, halogen, -COOH, -CN, optionally substituted C1-C6 alkyl, optionally substituted 6-16 membered aryl, optionally substituted 5-16 membered heteroaryl, optionally substituted 4-8 membered saturated or unsaturated cycloalkyl, optionally substituted 4-8 membered saturated or unsaturated heterocyclic group, optionally substituted C1-C6 alkylcarbonyl, optionally substituted -C O-(C1-C6 alkyl), -C (NR a R b), dihydroxyboryl, optionally substituted C2-C8 alkenyl, optionally substituted C2-C8 alkynyl, optionally substituted C1-C6 alkyl sulfonyl group, optionally substituted C1-C6 alkyl sulfoxide group and optionally substituted C1-C6 alkyl mercapto group; wherein, the heteroaryl or heterocyclic group contains 1-3 heteroatoms selected from N, O, S, P; wherein, R a and R b are each independently selected from the group consisting of H, optionally substituted C1-C6 alkyl, optionally substituted 3-8 membered cycloalkyl, and optionally substituted 4-8 membered heterocyclic group, or R a and R b are connected together with N to form an optionally substituted 4-8 membered heterocyclic ring; wherein the heterocyclic ring contains 1-3 heteroatoms selected from N, O, S and P; R 7 is selected from the group consisting of H and optionally substituted C1-C6 alkyl; R 8 and R 9 are each independently selected from the group consisting of hydrogen, deuterium and optionally substituted C1-C6 alkyl; the optionally substituted substituents in R 2, R 7, R 8, R 9, R 10, R a and R b include one or more substituents selected from the group consisting of H, halogen, C1-C4 alkyl, C1-C4 haloalkyl, nitro, -OH, amino, methoxy and dimethylamino. R 1 is selected from the group consisting of R 10 is selected from the group consisting of H, halogen, -NH 2, -NO 2, optionally substituted C1-C6 alkyl and optionally substituted C1-C4 alkoxy; R 2 is selected from the group consisting of H, halogen, cyano and optionally substituted C1-C6 alkyl; R 3 is R 6 and R 6' are each independently selected from the group consisting of H, methyl, ethyl, propyl and cyclopropyl, and at least one of R 6 and R 6' is H; X is an optionally substituted saturated or unsaturated 4-7 membered cyclic hydrocarbyl group or an optionally substituted 4-7 membered saturated or unsaturated heterocyclic group, and the heterocyclic group contains 1-2 heteroatoms selected from O, N, S and P; R 4 and R 5 are independently selected from the group consisting of H, halogen, -COOH, -CN, optionally substituted C1-C6 alkyl, optionally substituted 6-16 membered aryl, optionally substituted 5-16 membered heteroaryl, optionally substituted 4-8 membered saturated or unsaturated cycloalkyl, optionally substituted 4-8 membered saturated or unsaturated heterocyclic group, optionally substituted C1-C6 alkylcarbonyl, optionally substituted -C O-(C1-C6 alkyl), -C (NR a R b), dihydroxyboryl, optionally substituted C2-C8 alkenyl, optionally substituted C2-C8 alkynyl, optionally substituted C1-C6 alkyl sulfonyl group, optionally substituted C1-C6 alkyl sulfoxide group and optionally substituted C1-C6 alkyl mercapto group; wherein, the heteroaryl or heterocyclic group contains 1-3 heteroatoms selected from N, O, S, P; wherein, R a and R b are each independently selected from the group consisting of H, optionally substituted C1-C6 alkyl, optionally substituted 3-8 membered cycloalkyl, and optionally substituted 4-8 membered heterocyclic group, or R a and R b are connected together with N to form an optionally substituted 4-8 membered heterocyclic ring; wherein the heterocyclic ring contains 1-3 heteroatoms selected from N, O, S and P; R 7 is selected from the group consisting of H and optionally substituted C1-C6 alkyl; R 8 and R 9 are each independently selected from the group consisting of hydrogen, deuterium and optionally substituted C1-C6 alkyl; the optionally substituted substituents in R 2, R 7, R 8, R 9, R 10, R a and R b include one or more substituents selected from the group consisting of H, halogen, C1-C4 alkyl, C1-C4 haloalkyl, nitro, -OH, amino, methoxy and dimethylamino.