A dehydrant for a dehydration reaction of a key intermediate for synthesizing arbutin in the existing technical route is boron trifluoride diethyl etherate; ether belongs to a flammable and explosivearticle; another dehydrant is strong acid such as sulfuric acid and p-toluenesulfonic acid; such dehydrant is poor in reaction selectivity and very low in yield, generates much waste acid at the sametime and causes very high environmental protection pressure. For that reason, the invention provides a method of synthesizing arbutin by taking solid superacid as a catalyst. The method comprises thefollowing steps: preparing a solid superacid catalyst, preparing an intermediate Arb-1 by using the solid superacid as the catalyst, preparing an intermediate Arb-2 from Arb-1 by using the solid superacid as the catalyst, recovering and activating the catalyst, and performing reaction and purification using the intermediate Arb-2, methanol and sodium methoxide to form arbutin. The method has the advantages that the method causes little waste gas, waste water and industrial residue, and is green, environmentally friendly, simple and convenient in technical operation and suitable for industrialization.