The invention provides a quinolinedione derivative and pharmaceutically acceptable salts thereof. The above compounds comprise optical isomers, tautomers and stereoisomers under an application condition, and pharmaceutically acceptable salts, solvates, hydrates or crystal forms thereof. The compounds are an active ligand of a novel cannabinoid II receptor CB2 and can be used for preparing medicines for controlling and alleviating CB2 receptor mediated diseases, and the medicines are agonists, partial agonists, inverse agonists or antagonists of the agonist CB2 receptor. The compounds have a structural general formula B shown in the specification.