The study was aimed to investigate the immunophenotypic and cytogenetic features of chronic lymphocytic leukemia (CLL) in order to provide an evidence for diagnosis and therapy. Immunophenotypic analysis was performed by using a panel of monoclonal antibodies and three-color immunofluorescence staining methods of flow cytometry in 51 patients with CLL, and the cytogenetic features were analyzed by R-banding technique. The results indicated that among 51 CLL cases, the positive rate of CD19 and CD23 was 96.1%, followed by CD15 (94.1%), CD20 (82.4%) and CD22 (78.4%). The positive rate of CD38 was 23.5%. Forty-six patients expressed both CD5 and CD19. Seven main clonal chromosomal abnormalities were detected by conventional cytogenetics (CC) in eighteen cases (35.3%), with three cases of +12, two cases of 13q(-), other chromosomal abnormalities included +14, 6q(-), t (11; 14), t (14; 18) and t (2; 7). Expression of the antigens had no relationship with chromosomal abnormalities. It is concluded that typical CLL express CD5, CD19 and CD23, and the positive rate detected by CC in CLL is low. Immunophenotyping in combination with cytogenetic technique plays an important role in the diagnosis and prognosis of CLL.