AIM:To observe themorphological features of corneal endothelial cells in acute episode of anterior uveitis, and to explore the damage mechanism of corneal endothelial by fresh keratic precipitates (KP). METHODS:Fifty cases(50 eyes) with acute anterior uveitis of first time onset were selected in this study. Inflammation lasted for 3 days or more, KP≥(+++) as acute attack group (group A). Inflammation receded completely, KP(-) as group B. The opposite eye with no onset of acute anterior uveitis as group C. All people were measured by non-contact corneal specular microscopy, which included cell density(CD), hexagonality(HG), average size(AVG), standard deviation of the average cell area(SD), the variation coefficient of the cells in the area(CV), and the central corneal thickness(CCT) was measured. Then the data were compared and analyzed.RESULTS:Compared with group C, CD and HG of group A reduced, AVG, SD, CV, CCT of group A increased, the difference were statistically significant(P<0.05). Compared with group C, HG of group B reduced, CV increased, the difference was statistically significant(P<0.05). Compared with group B, HG of group A reduced, CCT and CV increased, which had statistical significance(P<0.05). Comparison among three groups showed that CV and HG had statistical significane（P＜0.05）.CONCLUSION:Fresh KP of acute anterior uveitis can increase the corneal thickness, change the form of endothelial cells and also reduce their function. After the alleviation of inflammation, corneal thickness tends to normal, but changing patterns of cells persisted.