Background The scar formation of filtering bleb is a cause of filtering operation failure.The topical application of mitomycin C (MMC) can inhibit the growth of collagenous fiber and improve function of bleb.However,some adverse effects of MMC are being closely concerned.Many studies have conformed the efficacy of amniotic membrane in filtering operation,but the comparison study between MMC and amniotic membrane is still lack.Objective Purpose of this study was to evaluate the anti-scarring effectiveness of amniotic membrane after its use in the filtrating surgery.Methods A randomized,controlled trial was designed.This study was approved by Ethic Committee of Peking University Third Hospital Eye Center.Written informed consent was obtained from each patient initial of this study.Fifty-two eyes of 47 patients with primary glaucoma were included in Peking University Third Hospital Eye Center from October 2009 to October 2011.The eyes were divided into two groups according to single blindness design and randomized digital table.Trabeculectomy combined with amniotic implantation was performed in the patients of the amniotic group,and trabeculectomy combined with 0.02％ MMC in the patients of the MMC group.The patients were followed-up for 3 months.Intraocular pressure (IOP),the anterior chamber depth,filtering bleb shape,incidence of complication and operative efficacy were measured and evaluated.Results No significant difference was found in the demography between two groups (P＞0.05).Seventeen patients in the MMC group and twenty-two patients in the amniotic group finished the trial.The IOP in the amniotic membrane group was (16.60-±5.04) mmHg on the third month after operation and that before operation was(23.52±-6.52) mmHg.In the MMC group,the IOP was(24.09± 12.79) mmHg on the third months after operation,and that before operation was (17.04±3.69) mmHg.Significant difference was found in the IOP between preoperation and postoperation in both groups(P＜0.05).IOP differential value on the third month was 6.98 mmHg in the amniotic membrane group and 6.94 mmHg in the MMC group.No significant differences were seen in the IOP between the amniotic membrane group and the MMC group in 1 week,2 weeks,1 month and 3 months(t=0.972,P=0.336;t=-0.512,P=0.611;t =-0.372,P =0.712 ; t =0.427,P =0.672).There were no significant differences in the number of eyes in the height grade,vascularization and perimeter classification of the filtering blebs 1 week,2 weeks and 1 month after surgery between these two groups (x2 =0.991,P =0.320 ; x2 =0.474,P =0.491 ; x2 =2.008,P =0.156).The total effective rate of surgery was 90.49％ in the amniotic membrane group and 100％ in MMC group,with a significant difference between them(x2 =26.180,P=0.000).There were not significantly different in the incidences of bleb leakage in 1 week,2 weeks and 1 month after operation between the MMC group and the amniotic group(x2 =3.556,P =0.059;x2=1.129,P=0.800; x2=0.434,P =0.510).Conclusions Combination of trabeculectomy with amniotic implantation has a similar lowing-IOP effect to trabeculectomy combined with MMC.The incidence of bleb leakage in the trabeculectomy combined with amniotic implantation dose not increase when compare with trabeculectomy combined MMC.