Abstract: Objective To observe the effect of temozolomide (TMZ) - polylactic acid/glycolic acid (PLGA) release microspheres (MS) on viability and apoptosis of glioma cell. Methods C6 glioma cell samples were divided into experimental group and control group. TMZ - PLGA release microspheres was added into experimental group with the drug loading of 2.5%, 5%, 7.5% and 10%, and only PLGA was added into blank control group. Cell activity was detected with automatic microplate reader and cell apoptosis rate was analyzed with multi-parameter flow cytometry. Results The apoptosis rate of tumor cell in experimental group with drug loading of 2.5%, 5%, 7.5% and 10% on day 14 were 30.45%±0.24%, 35.87%±0.58%, 41.56%±0.82%, 43.34%±1.24%, respectively. Compared with apoptosis rate in control group (3.02%±0.24%), it could kill C6 glioma cells effectively, and the effect enhanced with the increasing of drug loading (P＜0.05). The viability of C6 glioma cells detected using MTT was 23.47%±2.65%, 14.58%±5.76%, 6.24%±7.32% and 4.36%±2.41% in experimental group with drug loading of 2.5%, 5%, 7.5% and 10% on day 3, compared with control group (99.60%), the tumor cell activity could be inhibited effectively in experimental groups, and the effect enhanced with the increasing of drug loading (P＜0.05), but there was no significant difference between group of 7.5% and group of 10%. Conclusion The C6 glioma cells can be killed by TMZ-PLGA release microspheres of different degree of drug loading. Within a certain range, the higher the drug loading of release microsphere is, the stronger the effect of inhibiting of glioma cells is.