Objective To investigate the long term efficacy of vitrectomy in the treatment of acute retinal necrosis syndrome (ARN).Methods The clinical data of 17 patients (19 eyes) with ARN underwent vitrectomy were retrospectively analyzed. The diagnosis of ARN was made by clinical symptoms, slit lamp and indirect ophthalmoscope examination. Preoperative best corrected visual acuity (BCVA) ranged from no light perception to 0.1 (only one eye with 0.1). Eighteen eyes had retinal detachment (RD). All 19 eyes underwent one to five times (on average of 2.8 times) conventional pars plana vitrectomy (PPV). 18/19 eyes (94.7%) underwent multiple times of PPV. The followup period ranged from 12 to 120 months with an average of 44 months.Results Complete retinal reattachment was achieved in 17/18 (88.9%) eyes at the next day after the first PPV. The major indications for second or more times PPV included removal of silicon oil, proliferative retinopathy and hypotony. Nine eyes had a BCVAge;0.1 during the followup, but only four eyes had a BCVAge;0.1 at the end of followup. The mean IOP of 19 eyes with silicone oil tamponade was 12.7 mm Hg（1 mm Hg=0.133 kPa）, and the mean IOP of 15 eyes without silicone oil tamponade was 5.1 mm Hg. All eyes had variable degrees of postoperative proliferative retinopathy, and eight eyes developed atrophy of eyeball at the end of the follow-up.Conclusion PPV has no long-term beneficial effects on ARN.