The invention discloses a preparation method of a hyperbranched poly(beta-cyclodextrin) containing an azide group. The preparation method comprises the following steps of: firstly, preparing a hexa-monosubstituted azido beta-cyclodextrin monomer from hexa-monosubstituted paratoluene sulfonylated beta-cyclodextrin, potassium iodine and sodium azide; secondly, preparing a polysilicon hydrogenated beta-cyclodextrin monomer containing hexa-mono azide from the hexa-monosubstituted azido beta-cyclodextrin monomer, dimethyl dichlorosilane and pyridine; and lastly, preparing the hyperbranched poly(beta-cyclodextrin) containing an azide group from the polysilicon hydrogenated beta-cyclodextrin monomer containing hexa-mono azide and divinyl tetramethyldisiloxane. By adopting the method, complex steps in monomer synthesis are simplified, the branching coefficient of the poly(beta-cyclodextrin) and the proportion of cyclodextrin molecules have higher controllability, and the outer end of the poly(beta-cyclodextrin) can be quickly modified by effectively utilizing a click chemistry reaction.