Objective:To investigate the effect of tauroursodeoxycholic acid (TUDCA) on the apoptosis of INS-l cells cultured by palmitate in vitro. Methods: INS-1 cells were cultured in the presence of different concentrations of palmitate(0.25,0.50,1.00 mmol/L) or comlined with TUDCA(100 μmol/L) for 24 h. Cell viability was evaluated with MTT reduction conversion assay. The annexin-V/FITC cell death detection kit was used to monitor cell apoptosis. The expressions of endoplasmic reticulum(ER) stress marker GRP78 were detected by Western blotting. Results: The proliferation of INS-1 cells was inhibited,and the apoptosis was induced significantly by palmimte(concentration≥0.5 mmol/L,P < 0.05). The apoptosis rate was significantly decreased when INS-l cells were co-cultured with TUDCA(P < 0.05). Moreover,the expression of GRP78 was increased in INS-1 cells incubated with palmitate(P < 0.05),and it was repressed by TUDCA(P < 0.05). Conclusion: Our results suggest that TUDCA could protect INS-1 cells from palmitate-induced apoptosis,and it might work through repressing the expression of ER stress response protein GRP78 and alleviating ER stress.