The synthesis of tri, hexa and nonasaccharide of O-polysacchardie of lipopolysaccharide (LPS) from Danish Helicobacter pylori has been accomplished. The key synthetic strategies are that the axial methyl group in the branched sugar was elaborated after the coupling of building blocks B and C and the branched sugar was introduced in between two rhamonoses of the trisaccharide repeat unit. Coupling of three monosaccharide building blocks and the dimerization and trimerization of the resulting trisaccharide repeat unit was achived by employing CB glycoside method.