Abstract: Objective: To investigate the effects of chloroquine( CQ) on the proliferation and apoptosis of nasopharyngeal carcinoma cells. Methods: The growth inhibition of CNE-2Z cells induced by different concentration CQ( at 0,2,4,8,16,32 mol / L of CQ) were detected by MTT assay. The effects of different concentration CQ on the colony formation were detected by colony cloning experiment. The apoptosis of CNE-2Z cells induced by CQ was detected by Propyl bromide organism dye. The expression of glucose-regulated protein 78( GRP-78),a marker for endoplasmic reticulum stress,in CNE-2Z cells treated with 10 mol / L of CQ at 0,6,16 and 24 h were detected by Western blot. Results: The different concentration CQ had obviously inhibition effects on CNE-2Z cells. The cell survival rates of CNE-2Z cells treated with 16 mol / L at 24,48 and 72 h were 85. 94%,75. 34% and 56. 45%,respectively. CQ could inhibit the colony formation,induce the apoptosis in a dose-dependent manner and increase the GRP-78 expression of CNE-2Z cells. Conclusions: CQ can inhibit the proliferation of CNE-2Z cells and induce their apoptosis through the overreaction mechanism of endoplasmic reticulum stress.