Abstract:  Objective To observe the efficacy of trans-conjunctival lower eyelid retractor plication with lateral tarsal strip to correct involutional lower eyelid ectropion. Design Retrospective case series. Participants Thirteen patients (13 eyelids) with primary involutional lower eyelid ectropion in Beijing Tongren Eye Center. Methods All patients were performed plication of inferior retractor to the lower border of tarsus via a transconjunctival approach. Lateral tarsal strip was also performed simultaneously in all cases. The follow-up was (7.1±2.5) months. Main Outcome Measures Morphology and position of eyelid, vertical relaxation of eyelids, horizontal relaxation of eyelids. Results Until the last follow-up, all patients recovered well. According to the ectropion grading scale, the grade of ectropion was significantly reduced. The preoperative ectropion grade was II~IV, and the postoperative grade was 0~I (Z=-4.652, P<0.0001). The preoperative vertical relaxation of eyelids was (7.04±0.52) mm, and postoperative was (4.31±0.51) mm (t=22.45，P<0.0001).The preoperative horizontal relaxation of lower eyelid was (9.5±0.91) mm, and postoperative was (5.19±0.52) mm (t=19.96, P<0.0001). There were no cases of overcorrection, recurrent ectropion, suture abscess, wound dehiscence, or inferior fornix shortening after surgery. Conclusions This small sample size study shows that trans-conjunctival lower eyelid retractor plication combined with lateral tarsal strip for primary involutional lower eyelid ectropion is effective and simple. (Ophthalmol CHN, 2022, 31: 315-318)