Objective To investigate the effects of congenital ptosis on refractive power of the corneal surface.Methods Forty-five patients (90 eyes) with congenital ptosis in the First Affiliated Hospital of Kunming Medical University were examined from October 2013 to June 2015.Corneal topographic analysis was performed in both the ptosis and the normal eyes.The comparison between the ptotic eye and the normal eye was done according to the topographic results.Results Among 90 eyes,55 were ptotic and 35 were normal.Amblyopia was detected in 21 ptotic eyes (38.2％).No correlation was found between amblyopia and the severity of ptosis (x 2=2.617,P＞0.05).Ptotic eye showed an asymmetrical bow tie pattern (23 eyes) and an irregular pattern (32 eyes) on corneal photography and the maximum refractive power occurred at the inferior quadrant of the corneal horizontal axis.Difference value of the average refractive power of the cornea between lower side and upper side in ptotic eyes was higher than that of the normal eyes at 5mm and 7mm diameter areas (P＜0.01) except for 3mm diameter area (P＞ 0.05).Conclusion Congenital ptosis may lead to the change of refractive power of the local corneal surface.Amblyopia has no correlation with the severity of ptosis.