Objective：To investigate significances of variation of telomerase activity and human telomerase reverse transcriptase （hTERT） mRNA in monitoring the inhibition of multiple myeloma（MM） U266 cell proliferation and apoptosis as a result of thalido－mide. Methods：Inhibition of thalidomide on cell proliferation was determined by CCK-8 assay. Percentage of U266 cell apoptosis was measured by flow cytometry. Telomerase activity of U266 cells was performed by TRAP-ELISA. RT-PCR was used to detect the ex－pressions of hTERT mRNA. Results：Thalidomide inhibited the growth of U266 cells and induced cells apoptosis in a time-dose dependent manner. Cells were treated with 10 μg/ml thalidomide for 24 h and 48 h；telomerase activities of U266 cells were respec－tively 7.96±0.09 and 7.65±0.07，showing no significant difference compared with those in control group（P =0.082 0）. Expressions of hTERT mRNA were 2.82±0.03 and 2.31±0.04 respectively，significantly different from those in control group（P=0.033 0）. Telom－erase activities and hTERT mRNA expressions of 50 μg/ml and 100 μg/ml groups were significantly different from those in con－trol group（P=0.002 8）. Conclusions：Thalidomide can inhibit U266 cell proliferation and induce its apoptosis，the mechanism of which is related with telomerase. Change is more sensitive in hTERT mRNA expression than in telomerase activity and it is an ef－fective index when treating MM with thalidomid.