Abstract: Objective To improve the diagnosis and therapy of aggressive natural killer cell leukemia. Methods The characteristics of aggressive NK cell leukemia and its treatment were discussed with review of literatures. Results After combination chemotherapy which contained l-asparaginase and methotrexate,the patient would have a good result.Conclusion As aggressive NK cell leukemia is rare, its diagnose should include clinical mainfestation,cell morphology,immunophenotype,gene rearrangement.Treatment with joint asparaginase and (or) methotrexate scheme is given prior to hematopoietic stem cell transplantation ,which may prolong survival period.

Key words: Natural killer cell, leukemia, aggressive, diagnosis, therapy