Abstract: Objective To discuss the clinical features, the immunophenotype， the cytogenetic change, the diagnosis and corresponded treatments of Waldenstrom's macroglobulinemia(WM). Methods One case of WM was analyzed. Results The female patient was proved to be macroglobulinemia by serum electrophoresis, bone marrow morphology and immunophenotype, etc. Then she got a good regression after eight cycles of chemotherapy, and is still being followed up regularly. Conclusion Special immunophenotype and genetic changes exist in WM. It is suggested that the immunophenotype and cytogenetics should be detected that the diagnosis of WM should be considered when patients have unexplained high level IgM.