The invention belongs to the field of molecular therapy and particularly relates to an IDH2 (isocitrate dehydrogenase 2) mutant type small-molecule inhibitor and an application thereof in the inhibition and killing of tumor cells. The IDH2 mutant type small-molecule inhibitor can be used for treating IDH2 mutant type acute myelogenous leukemia, glioma and osteosarcoma and has strong pertinence, the normal physiological activities are not influenced, immature leukocyte can be promoted to be mature, the harm caused to the body of a patient is relatively small, the clinical use effect is relatively good, and the remission rate is relatively high.