【Abstract】 Objective lb investigate the role and mechanism of stromal interaction molecule 1 (STIM1) in mesangial cells injury induced by high glucose. Methods Human glomerular mesangial cells were taken as study subjects. The experiment was divided into normal group (N group) , high glucose for 12 hours and 24 hours group(HG12h and HG24h group). Real-time PCR and Western-blot were used to detect the changes in STIM1 mRNA and protein expression of mesangial cells induced by high glucose at different time points. The changes of calcium in mesangial cells induced by high glucose were observed by laser confocal assay, and the apoptosis of mesangial cells was detected by Tunel assay. The effects of STIM1 siRNA gene transfection on calcium and apoptosis in mesangial cells were observed. Results The experiments showed that STIMlmRNA and protein were significantly increased in HG12h group compared with that of N group (P＜0.05). STIMlmRNA and protein were significantly increased in HG24h group compared with that of N group (P＜0.01 and P＜0.05, respectively). The results of laser confocal imaging showed that calcium in mesangial cells was significantly increased in HG12h group, HG24h group compared with N group (P＜0.05). liinel assay showed that the apoptosis of mesangial cells increased in HG12h group, HG24h group compared with N group (P＜0.01). The intracellular calcium and apoptosis significantly reduced in STIMlsiRNA gene transfection group compared with non-transfection group(P＜0.05). Conclusion High glucose can induce intracellular calcium changes and apoptosis of mesangial cells, in which STIM1 plays an important role.