Objective:To establish a method for the determination of antioxygen 1178 in 5-layer co-extrusion bags used for infu-sion. Methods:A Uitimat XB-C8 (250 mm × 4. 6 mm,5μm) column was used,the mobile phase was methanol-water with gradient elu-tion, the flow rate was 1. 0 ml·min-1 ,the detection wavelength was 223 nm,the column temperature was 35℃ and the injection vol-ume was 20 μl. Results:The concentration of antioxygen 1178 had the linear relationship within the range of 1. 64-205. 10 μg·ml-1 (r=0. 999 9),and the average recovery was 92. 05% (RSD=1. 94%, n=9). Conclusion:The method is accurate,stable and spe-cific,and can be used to determine antioxygen 1178 in 5-layer co-extrusion bags used for infusion.