Objective To explore the clinical and laboratory characteristics of chronic B lymphocyte proliferation disease (B-CLPD) without typical lymphoid proliferation. Methods The clinical records of patients with B-CLPD only characterized by pancytopenia form January 2007 to March 2016 in hematology department of Xinjiang Uygur Autonomous Region People ' s Hospital were collected, and the cell morphology, bone marrow pathology, cytogenetics and molecular characteristics were retrospectively analyzed. Results The median age of 11 patients was 68 years old. The lymphocyte ratio of peripheral blood smears in all patients increased in different level (0.36-0.68), but absolute lymphocyte count was normal or decreased (0.59×109-1.99×109). Lymphocyte-like plasma cell or small numbers of plasma cell can be seen in the bone marrow smears of 4 cases and lymphocytes with irregular burr-like protrusions were observed in 2 cases while there were no characteristic morphological changes in remained 5 cases. Immunophenotypical analysis showed that all patients expressed CD19, CD20, CD22, SmIg, not expressed CD5, CD10 which with scores of 0-2 according to chronic lymphocytic leukemia (CLL) points system;CD103, CD11C, CD25 and FMC7 were highly expressed in 2 cases while there were no characteristic expression in remaining cases. There were no abnormal karyotypes observed from the conventional cytogenetic and fluorescence in situ hybridization (FISH) analysis (both of IgH/CCND1, bcl-2/IgH were negative) in all patients. 8 patients were found IgH gene rearrangement, MYD88L256P and BRAF V600E was positive in 5 cases and 2 cases respectively. 5 cases were diagnosed as Waldenstrom macroglobulinemia, 3 cases were B-CLPD, 2 cases were hairy cell leukemia, 1 case was nodal marginal zone B-cell lymphoma after comprehensive analysis of their clinical and laboratory data. Conclusion Even if there are no increased peripheral blood lymphocytes in pancytopenia patients, it is necessary to perform bone marrow smears, immunophenotyping, IgH gene rearrangement, cytogenetics and other molecular laboratory tests to exclude B-CLPD, and reduce misdiagnosis.