〔Abstract〕 Objective To explore the damaging effect of the IP3-protein kinase C pathway on human retinal vascular endothelial cells under high glucose conditions. Methods Human retinal vascular endothelial cells in the logarithmic growth phase were taken and divided into the experimental group(10 mmol/L glucose and 20 mmol/L glucose) and the control group(5 mmol/L glucose). The morphological changes of cells were observed under different concentrations of glucose culture medium. The apoptosis of human retinal vascular endothelial cells was detected by flow cytometry. Real-time fluorescent quantitative reverse transcription polymerase chain reaction was used to detect the RNA expression level of PKC in the IP3-protein kinase C(PKC) pathway, and Western blot was used to detect the protein expression level of PKC in cells. Results Under high glucose conditions, the volume of human retinal vascular endothelial cells increased, the degree of extension decreased, and the apoptosis rate increased. Compared with the control group, the apoptosis rate of human retinal vascular endothelial cells in the 20 mmol/L glucose group increased(P<0.05); the IP3 level of human retinal vascular endothelial cells in the 20 mmol/L glucose group(587.9±15.2) ng/ml was lower than that of the control group(738.9±1.0) ng/ml(P<0.05). Under high glucose treatment, the expression levels of PKC mRNA and protein increased(P<0.05). Conclusion The IP3-PKC pathway may be involved in the damage process of human retinal vascular endothelial cells under high glucose conditions, and thus may play a role in diabetic retinopathy.