AIM:To study the method and effect of using Nd:YAG laser in treating posterior capsular opacities after mydriasis.METHODS:After mydriasis posterior capsular opacities treated with Nd:YAG laser posterior capsulotomy.RESULTS:The success rate of the operation was 99.8%.The best corrected visual acuity (BCVA) was improved significantly in 97.2% cases(BCVA≥0.4) by Nd:YAG laser therapy after mydriasis.CONCLUSION:After mydriasis,Nd:YAG laser posterior capsulotomy is a kind of effective,safe,simple and low-rate complication technique in treating after cataract.