AIM:To investigate the effect of levator shortening under microscope and micro-instrument.METHODS:Eighteen cases(20 eyes) with congenital ptosis were treated levator shortening under microscope.RESULTS:The follow-up of all cases ranged from 0.5 to 2 years postoperatively.18 eyes obtained fine results.2 eyes were effective.CONCLUSION:Levator shortening under microscope is an effective method.The anatomical structure is clear.Its hurt is slight,and it has accurate operation and less surgical time.