A compound of formula or a pharmaceutically acceptable salt thereof, wherein, R 1 is connected with R 2 to form a 4-6-membered ring substituted with two R 5; L 1 is selected from a single bond, -(C 2) m -, -O(C 2) m -, -S(C 2) m -; m is independently selected from 0, 1, or 2, respectively; R 5 is independently selected from H, halogen, OH, CN, NH 2, respectively, or independently selected from C 1-5 alkyl, C 1-5 heteroalkyl, C 3-6 cycloalkyl and 3-6-membered heterocycloalkyl, C 1-5 alkyl, C 1-5 heteroalkyl, C 3-6 cycloalkyl and 3-6-membered heterocycloalkyl being optionally substituted with one, two or three R; R 3 is selected from H, or selected from C 1-3 alkyl, C 1-3 heteroalkyl, C 1-3 alkyl and C 1-3 heteroalkyl being optionally substituted with one, two or three R; L 2 is selected from the group consisting of a single bond, -O-, -NH-; L 3 is selected from the group consisting of -C 2 -; ring A is selected from the group consisting of phenyl, 5-10-membered heteroaryl; R 4 is independently selected from the group consisting of H, halogen, C 1-3 alkyl, C 1-3 heteroalkyl, C 2-3 alkynyl, respectively; R is independently selected from H, OH, CN, NH 2, halogen, respectively, or selected from C 1-3 alkyl and C 1-3 heteroalkyl, C 1-3 alkyl and C 1-3 heteroalkyl being optionally substituted with one, two or three R'; the "hetero" of said C 1-5 heteroalkyl, said C 1-3 heteroalkyl, said 3-6-membered heterocycloalkyl, said 5-9-membered heteroaryl is selected from the group consisting of -O-, =O, N, -NH-, -S-, =S, -S(=O)-, -S(=O) 2 -,-C(=O)O-, -C(=O)NH-, -S(=O)NH-; R' is selected from the group consisting of F, Cl, Br, I, OH, CN, NH 2; in any of the above cases, the number of heteroatoms or heteroatom-containing groups is independently selected from 1, 2 or 3, respectively. R 1 is connected with R 2 to form a 4-6-membered ring substituted with two R 5; L 1 is selected from a single bond, -(C 2) m -, -O(C 2) m -, -S(C 2) m -; m is independently selected from 0, 1, or 2, respectively; R 5 is independently selected from H, halogen, OH, CN, NH 2, respectively, or independently selected from C 1-5 alkyl, C 1-5 heteroalkyl, C 3-6 cycloalkyl and 3-6-membered heterocycloalkyl, C 1-5 alkyl, C 1-5 heteroalkyl, C 3-6 cycloalkyl and 3-6-membered heterocycloalkyl being optionally substituted with one, two or three R; R 3 is selected from H, or selected from C 1-3 alkyl, C 1-3 heteroalkyl, C 1-3 alkyl and C 1-3 heteroalkyl being optionally substituted with one, two or three R; L 2 is selected from the group consisting of a single bond, -O-, -NH-; L 3 is selected from the group consisting of -C 2 -; ring A is selected from the group consisting of phenyl, 5-10-membered heteroaryl; R 4 is independently selected from the group consisting of H, halogen, C 1-3 alkyl, C 1-3 heteroalkyl, C 2-3 alkynyl, respectively; R is independently selected from H, OH, CN, NH 2, halogen, respectively, or selected from C 1-3 alkyl and C 1-3 heteroalkyl, C 1-3 alkyl and C 1-3 heteroalkyl being optionally substituted with one, two or three R'; the "hetero" of said C 1-5 heteroalkyl, said C 1-3 heteroalkyl, said 3-6-membered heterocycloalkyl, said 5-9-membered heteroaryl is selected from the group consisting of -O-, =O, N, -NH-, -S-, =S, -S(=O)-, -S(=O) 2 -,-C(=O)O-, -C(=O)NH-, -S(=O)NH-; R' is selected from the group consisting of F, Cl, Br, I, OH, CN, NH 2; in any of the above cases, the number of heteroatoms or heteroatom-containing groups is independently selected from 1, 2 or 3, respectively.