Abstract: Using cellulose acetoacetate as main chain and glucose, cellobiose and cellulose nanocrystals as branch chain, saccharide branched cellulose was synthesized by Biginelli reaction. The molecular structure of saccharide branched cellulose was characterized by NMR spectrum, Infrared spectroscopy, Elemental analysis and X-ray diffraction. The results showed that the emergence of new functional groups of \mathrmC=\mathrmC、(\mathrmC=\mathrmO)—NH, C—N and —NH at the grafting point proved the successful preparation of glucose branched cellulose, cellobiose branched cellulose and cellulose branched cellulose. The results of single factor experiment showed that the optimum reaction conditions for the synthesis of the three kinds of saccharide branched cellulose were solvent pH of 5-6, reaction time of 10 h and reaction temperature of 70 ℃. Among them, when the saccharide branch chain was glucose(branch chain degree of polymerization was 1) and the consumption was 0.6, the main chain degree of substitution was 0.87, the degree of branching of glucose branched cellulose was the highest, up to (11.82±0.57)% and the yield reached (90.70±1.82)%. When the saccharide branch chain was cellobiose(branch chain degree of polymerization was 2) and the consumption was 0.4, the main chain degree of substitution was 0.87, the degree of branching of cellobiose branched cellulose was the highest, up to (7.30±0.11)% and the yield reached (90.25±2.15)%. When the saccharide branch chain was cellulose nanocrystal(branch chain degree of polymerization was 100) and the consumption was 0.01, the main chain degree of substitution was 0.87, the degree of branching of cellobiose branched cellulose was the highest, up to (0.68±0.09)% and the yield reached (92.45±1.25)%.