This study was aimed to investigate whether 2-methoxyestradiol (2ME2) could exert effect of inducing differentiation on myeloma cells. A myeloma cell line CZ-1 secreting lambda light chain protein was used as an object of study. The CZ-1 cell morphology was observed by Wright's staining, the CD49e expression on cell surface after treatment with 2ME2 was detected by flow cytometry, the concentration of lambda light chain protein in the supernatant was assayed by immuno-scattering turbidity method. The results showed that treatments with 0.1-0.5 micromol/L 2ME2 for 72 hours resulted in some mature morphological changes of CZ-1 cells, such as the ratio of karyoplasms going down, nucleolus reducing or disappearing, chromatin getting rougher and more compacted; the CD49e positive CZ-1 cells increased by 2ME2 with concentrations of 0.1 micromol/L to 0.5 micromol/L in a concentration-dependent manner. The statistical difference from the control group was significant; the concentration of lambda light chain protein increased from control group 29.3 +/- 2.77 microg/ml to 35.97 +/- 2.6 microg/ml (P < 0.05) after exposure to 0.1 micromol/L 2ME2 for 72 hours, and the treatment of 0.5 micromol/L 2ME2 up-regulated lambda light chain protein to 79.67 +/- 1.88 microg/ml (P < 0.01) continuously. It is concluded that 2ME2 at low-concentration can induce differentiation of the CZ-1 cells to mature, which provides a new, and safe strategy for myeloma therapy.