Purpose: To investigate the influence of phacoemulsification on corneal endothelial cells in diabetes patients and normal controls.Methods: Phacoemulsification and intraocular lens implantation were performed on 75 patients with diabetic cataract (126 eyes) who were divided into two groups: Trial group 1 (Glu≤6 mmol/L); Trial group 2 (Glu 6-10 mmol/L) and 65 non-diabetic controls (112 eyes). The density and percentage of hexagonal cells and coefficient of variation of thecorneal endothelia were measured before surgery and 1 day,1 month and 3 months postoperatively.Results: There was no statstical difference in the density and percentage of hexagonal cells and coefficient of variation of the corneal endothelia prior to phacoemulsification (P＞0.05) between the three groups. The density and percentage of hexagonal cells of the corneal endothelia decreased signifi cantly after surgery in all three groups(P＜0.05), while the Coefficient of variation increased in all groups (P＜0.05). The rate of loss of corneal endothelial cells in the diabetic groups was significantly higher than for the control group (P＜0.05),the percentage of hexagonal cells in the diabetic groups was significantly lower than for the control group (P＜0.05), and the coefficient of variation in the diabetic groups was significantly higher than for the control group (P＜0.05) at 1 day,1 month and 3 months post-operatively. There was no statistical difference between the two diabetic groups in terms of these post-operative measurements.Conclusion: The corneal endothelium of diabetic patients is more prone to damage from phacoemulsification. It is advisable to evaluate the corneal endothelium routinely prior to phacoemulsification, particularly in diabetic persons.