The invention relates to a co-production method of calcium sulfate whisker and phosphoric acid. The method comprises the following technical steps of: (1) acid-hydrolyzing phosphate rock powder by hydrochloric acid with the mass concentration of 15 to 26% or nitric acid with the mass concentration of 20 to 90%, filtering the acid-hydrolyzed slurry into the acid hydrolysis solution containing Ca2<+>; (2) using the acid hydrolysis solution containing Ca2<+> and the sulfuric acid with the mass concentration of 20 to 90% as the raw materials, wherein the use level of the sulfuric acid is 100% of the needed theoretical amount of the sulfuric acid when the Ca2<+> in the acid hydrolysis solution and the sulfuric acid react completely, adding the sulfuric acid to the acid hydrolysis solution containing Ca<2+> under the stirring condition, reacting the sulfuric acid with the acid hydrolysis solution containing Ca2<+> at the normal pressure and at 50 to 90 DEG, filtering and separating the calcium sulfate whisker after the reaction is finished, and then washing and drying the calcium sulfate whisker; and (3) carrying out the counter-current extraction on the filtrate obtained in the step (2), wherein the extracted water phase is the phosphoric acid, and acid-hydrolyzing the phosphate rock powder by using the hydrochloric acid obtained by the counter-extraction of the soft water to the extracted organic phase which is separated in the counter-current extraction.