This study aims to investigate the phenolic acid from Indocalamus victorialis Keng f.and its antioxidant activity in vitro.The leaves from I. victorialis were extracted by microwave with 50% ethanol and the extraction was extracted with petroleum ether and n-butanol in order.Ten phenolic acids were isolated from n-butanol extraction by repeated separation and purification with silica gel column chromatography,Sephadex LH-20 gel column chromatography and semi-preparative HPLC,their structures were identified as myrosinic acid (1),ferulic acid (2),p-coumaric acid (3),syringic acid (4),caffeic acid (5),vanillic acid (6),chlorogenic acid (7),p-hydroxybenzoic acid (8),gentaric acid (9) and protocatechuic acid (10).The mixture of natural phenolic acids from I. victorialis leaves was obtained by semi-preparation from n-butanol extract,and then mixed into a series of solutions with the same concentration of V_C to carry out in vitro antioxidant control experiments.The scavenging rate of V_C was similar to that of the positive control at 5.0 mg/mL,the scavenging rate was 79.01% and 70% respectively,indicating that the phenolic compounds in I. victorialis leaves had strong antioxidant activity.