OBJECTIVE： To separate and purify oligosaccharide and polysaccharide from the flowers of Magnolia officinalis， and to investigate their in vitro antioxidant capacity. METHODS： Using 80％ ethanol as extraction solvent， the flowers of M. officinalis were extracted by reflux extraction and purified by column chromatogram to obtain oligosaccharide. The dregs of oligosaccharide extraction was used as raw material， and were extracted by hot water reflux extraction and purified by segmentation purification to obtain polysaccharide. Using 2，6-di-tert-butyl-4-methylphenol （BHT） as positive control， in vitro antioxidant capacity of different concentrations of oligosaccharide and polysaccharide from the flowers of M. officinalis （0.1， 0.2， 0.4， 0.6， 0.8， 1.0， 1.2  mg/ml） were investigated through clearance rate test， reducing capacity test， total antioxidant activity test of 1，1-diphenyl-2-trinitrophenylhydrazine （DPPH） free radical. RESULTS： DPPH free radical clearance， reducing capacity and total antioxidant activity were enhanced as the increase of oligosaccharide and polysaccharide concentration， when the concentration of oligosaccharide and polysaccharide ranged 0.1-1.0 mg/ml. In 3 tests， antioxidant activity index of oligosaccharide were similar to those of BHT （P＞0.05） when the concentrations were 0.8-1.0， 0.2-1.0， 0.1-1.0 mg/ml. In 3 tests， most of antioxidant activity index of oligosaccharide were slightly higher than those of polysaccharide， without statistical significance （P＞0.05）. CONCLUSIONS： The oligosaccharide and polysaccharide from the flowers of M. officinalis show good in vitro antioxidant capacity， and in vitro antioxidant capacity of oligosaccharide is better than that of polysaccharide.