Neutral sugar,uronic acid,amino sugar and sialic acid were effectively determined simultaneously by gas chromatography after methanolysis and trimethylsilylation.Three standard monosaccharide mixtures(including Ara,Rha,Fuc,Xyl,Man,Gal,Glc,GlcA,GalA,GalNAc,GlcNAc,Neu5Ac) and two polysaccharide samples(okara polysaccharide DFP,Coprinus comatus polysaccharide F32) were methanolysis by 1 mol/L HCl/methanol at 85 ℃ for 18~24 h,neutralized with Ag2CO3 and re-N-acetylated by adding acetic anhydride for 24 h in the dark.After removing the silver salts,the dried residue was trimethylsilylated by adding silylation reagent(pyridine/hexamethyldisilazane/chlorotrimethylsilane = 5∶ 1∶ 1) for 30 min at room temperature.Then the final products were analyzed by gas chromatography.This method needs fewer amount of sample,and has higher sensitivity and resolution.It can simultaneous detect kinds of monosaccharides.It will have a great potential for application.