Abstract: The existing synthetic methods of 1, 2, 3, 4, 6-penta-O-aceytl-β-D-mannopyranose, 2, 3, 4, 6-tetraO- aceytl- 1- bromide- α- D- mannopyranose, 3, 4, 6- tri- O- acetyl- 1, 2- O- allyloxyethylidene- β- D-mannopyranose were modified in this paper. And the same time they were synthesized by the microwave assisted method firstly, and the best results were got by orthogonal experiment based on single factor investigation. Their optimum technology of synthesis were as follows:800W, 20 min, 70℃, molar ratio of mannose and acetic anhydride 1∶11. 400 W, 50min, 25℃, volume ratio of acetic anhydride and hydrogen bromide acetic acid solution 1∶3. 500 W, 40min, 30℃, molar ratio of 2, 6-dimethylpyridine and 2, 3, 4, 6-tetra-O-aceytl-1-bromide-α-D-mannopyranose 1∶1。