A compound of Formula, a stereoisomer thereof or a pharmaceutically acceptable salt thereof, wherein, T is selected from the group consisting of N and CR'; each R 1 is independently selected from the group consisting of H, F, Cl, Br, I, OH, NH 2, CN, C 1-3 alkyl and C 1-3 alkoxy; wherein the C 1-3 alkyl or C 1-3 alkoxy is optionally substituted with 1, 2 or 3 substituents independently selected from the group consisting of F, Cl, Br, I, OH, NH 2 and CN; R 2 and R 3 are each independently selected from the group consisting of H, F, Cl, Br, I, OH, NH 2 and C 1-3 alkyl, wherein the C 1-3 alkyl is optionally substituted with 1, 2 or 3 substituents independently selected from the group consisting of F, Cl, Br and I; R 4 is selected from the group consisting of C 1-6 alkyl, C 1-6 alkoxy, 3- to 7-membered heterocycloalkyl-O-, 3- to 7-membered heterocycloalkyl-C 1-6 alkyl-O-, C 3-6 cycloalkyl-O- and C 3-6 cycloalkyl-C 1-6 alkyl-O-, wherein the C 1-6 alkyl, C 1-6 alkoxy, 3- to 7-membered heterocycloalkyl-O-, 3- to 7-membered heterocycloalkyl-C 1-6 alkyl-O-, C 3-6 cycloalkyl-O- and C 3-6 cycloalkyl-C 1-6 alkyl-O- are each independently optionally substituted with 1, 2, or 3 R; R 5 and R 6 are each independently selected from the group consisting of H, C 1-3 alkyl and 3- to 7-membered heterocycloalkyl, wherein the C 1-3 alkyl and 3- to 7-membered heterocycloalkyl are optionally substituted with 1, 2, or 3 R; L is selected from the group consisting of -O-, -NR a -, -CR b1 R b2 -, -CR b1 R b2 -O-, and -CR b1 R b2 -NH-; R a is H; alternatively, R 4 is connected to R a to form a 5- to 7-membered heterocycloalkyl group optionally substituted with 1, 2, 3 or 4 R'; ring A is selected from the group consisting of phenyl and 5- to 10-membered heteroaryl; ring B is selected from the group consisting of n is selected from the group consisting of 1, 2, 3, 4 and 5; each R is independently selected from the group consisting of F, Cl, Br, I, OH, NH 2, CN, NR c1 R c2, C 1-3 alkyl, C 1-3 alkoxy, C 1-3 alkyl-NH-C(=O)-, C 1-3 alkylthio and 3- to 7-membered heterocycloalkyl, wherein the C 1-3 alkyl, C 1-3 alkoxy, C 1-3 alkyl-NH-C(=O)-, C 1-3 alkylthio and 3- to 7-membered heterocycloalkyl are optionally substituted with 1, 2, or 3 R'; R' is each independently selected from the group consisting of F, Cl, Br, I, OH, NH 2, CN and C 1-3 alkyl; R b1 and R b2 are each independently selected from the group consisting of H, F, Cl, Br, I and C 1-3 alkyl; R c1 and R c2 are each independently selected from the group consisting of H and C 1-3 alkyl; the 5- to 7-membered heterocycloalkyl, 5- to 10-membered heteroaryl and 3- to 7-membered heterocycloalkyl each contains 1, 2, 3 or 4 heteroatoms or heteroatom groups independently selected from the group consisting of N, -O-, -S- and -NH-. T is selected from the group consisting of N and CR'; each R 1 is independently selected from the group consisting of H, F, Cl, Br, I, OH, NH 2, CN, C 1-3 alkyl and C 1-3 alkoxy; wherein the C 1-3 alkyl or C 1-3 alkoxy is optionally substituted with 1, 2 or 3 substituents independently selected from the group consisting of F, Cl, Br, I, OH, NH 2 and CN; R 2 and R 3 are each independently selected from the group consisting of H, F, Cl, Br, I, OH, NH 2 and C 1-3 alkyl, wherein the C 1-3 alkyl is optionally substituted with 1, 2 or 3 substituents independently selected from the group consisting of F, Cl, Br and I; R 4 is selected from the group consisting of C 1-6 alkyl, C 1-6 alkoxy, 3- to 7-membered heterocycloalkyl-O-, 3- to 7-membered heterocycloalkyl-C 1-6 alkyl-O-, C 3-6 cycloalkyl-O- and C 3-6 cycloalkyl-C 1-6 alkyl-O-, wherein the C 1-6 alkyl, C 1-6 alkoxy, 3- to 7-membered heterocycloalkyl-O-, 3- to 7-membered heterocycloalkyl-C 1-6 alkyl-O-, C 3-6 cycloalkyl-O- and C 3-6 cycloalkyl-C 1-6 alkyl-O- are each independently optionally substituted with 1, 2, or 3 R; R 5 and R 6 are each independently selected from the group consisting of H, C 1-3 alkyl and 3- to 7-membered heterocycloalkyl, wherein the C 1-3 alkyl and 3- to 7-membered heterocycloalkyl are optionally substituted with 1, 2, or 3 R; L is selected from the group consisting of -O-, -NR a -, -CR b1 R b2 -, -CR b1 R b2 -O-, and -CR b1 R b2 -NH-; R a is H; alternatively, R 4 is connected to R a to form a 5- to 7-membered heterocycloalkyl group optionally substituted with 1, 2, 3 or 4 R'; ring A is selected from the group consisting of phenyl and 5- to 10-membered heteroaryl; ring B is selected from the group consisting of n is selected from the group consisting of 1, 2, 3, 4 and 5; each R is independently selected from the group consisting of F, Cl, Br, I, OH, NH 2, CN, NR c1 R c2, C 1-3 alkyl, C 1-3 alkoxy, C 1-3 alkyl-NH-C(=O)-, C 1-3 alkylthio and 3- to 7-membered heterocycloalkyl, wherein the C 1-3 alkyl, C 1-3 alkoxy, C 1-3 alkyl-NH-C(=O)-, C 1-3 alkylthio and 3- to 7-membered heterocycloalkyl are optionally substituted with 1, 2, or 3 R'; R' is each independently selected from the group consisting of F, Cl, Br, I, OH, NH 2, CN and C 1-3 alkyl; R b1 and R b2 are each independently selected from the group consisting of H, F, Cl, Br, I and C 1-3 alkyl; R c1 and R c2 are each independently selected from the group consisting of H and C 1-3 alkyl; the 5- to 7-membered heterocycloalkyl, 5- to 10-membered heteroaryl and 3- to 7-membered heterocycloalkyl each contains 1, 2, 3 or 4 heteroatoms or heteroatom groups independently selected from the group consisting of N, -O-, -S- and -NH-.