The invention relates to a preparation method for antimony-doped tin oxide powder. The preparation method comprises the following steps of mixing antimony trichloride, tin tetrachloride pentahydrate and a compounding ingredient, adding into a hydrochloric acid solution, and uniformly stirring a mixed solution to obtain transparent liquid; uniformly mixing a dispersing agent, tin tetrachloride pentahydrate, water and ethanol to obtain a base solution; dropwise adding the transparent liquid and an ammonium hydroxide precipitating agent into the base solution within 30 to 80 minutes in a double titration way, controlling reaction temperature to be 50 to 60 DEG C while stirring, and controlling final reaction pH to be 5 to 6; stopping stirring after titration, and performing curing to obtain precursor suspension; performing filtration, water washing, alcohol washing, azeotropic distillation, drying, grinding and calcination on obtained precursor precipitates. According to the method, tin and antimony are synchronously hydrolyzed and precipitated, and antimony is uniformly doped; the powder prepared by the method has the advantages of small particle size, loose structure, low agglomeration rate, high dispersibility and the like.