AIM:To study the clinical features and treatments of congenital superior oblique muscle paralysis.METHODS:Data of 52 patients 61 eyes with congenital superior oblique muscle paralysis were analyzed retrospectively.RESULTS:Congenital superior oblique muscle paralysis was common in congenital vertical strabismus.The binoculars vision of yournger patients was better.There was a typical compensatory head posture.The head tilt test was positive.without diplopia.CONCLUSION:Operation should be performed early once congenital superior oblique muscle paralysis is defined.