·AIM:To investigate the factors related to the decrease of corneal endothelial cell number after phacoemulsification in cataract patients. ·METHODS: We selected 98 patients (120 eyes) in Ophthalmic Center from July 2014 to July 2016 underwent phacoemulsification and they were retrospectively analyzed. According to the central corneal endothelial cell density before and 2mo after the operation, they were divided into serious loss group of 52 cases (67 eyes, density of central corneal endothelial cells loss rate no less than 12.3%),the general loss group of 46 cases (53 eyes, the density of central corneal endothelial cell loss rate <12.3%). Relevant indicators of general information, operation of the two groups were compared, the influence factors of non conditional Logistic regression analysis method was used to investigate the effect for corneal endothelial cell loss in cataract patients. ·RESULTS:Serious loss group and the general group on gender, rate with hypertension, rate with diabetes, rate with high blood lipids, with shallow anterior chamber, corneal diameter and suction time comparison, had no statistically significant differences (P > 0. 05). Nuclear hardness classification of Emery lens, ultrasonic power, ultrasonic emulsification time, age between groups were significantly different(P<0.05). By using Logistic analysis method, the results showed that increased Emery lens nucleus grading, ultrasonic energy, phacoemulsification time, age were independent risk factors for corneal endothelial cells after phacoemulsification (P<0.05). ·CONCLUSION: The main factors that influence the decrease of corneal endothelial cell number after phacoemulsification are Emery lens, higher grade of nucleus of lens, increase of ultrasonic energy, longer time of phacoemulsification and increased age.