The present invention relates to a disaccharide intermediate and a synthesis method thereof, relates to the chemical pharmaceutical field, and more specifically relates to a method for preparing a disaccharide segment of a key intermediate for chemically synthesizing heparin and heparinoid compounds. Disclosed are a new disaccharide intermediate and three methods for synthesizing the disaccharide intermediate, that is, compounds of a formula (4) and glucopyranose protected by different anomeric carbon are made to react in the presence of an active agent, to obtain the disaccharide intermediate. According to the technical solutions of the present invention, synthetic raw materials are easy to obtain, have a mild reaction condition, and are suitable for industrialized production.