The invention belongs to the technical field of inorganic nanometer materials and particularly discloses a method for template-free synthesis of phosphoric acid microspheres. The method specifically comprises the following steps of (S1) dissolving antimony potassium tartrate and phosphoric acid into a solvent to form a mixed solution, (S2) conducting solvo-thermal reaction on the obtained mixed solution and performing cooling, washing, centrifugal separationand drying to obtain a product, wherein the solvent is ethylene glycol or glycerol. The method adopts cheap and easily-obtained raw materials, and a large amount of phosphoric acid microspheres which is good in dispersity and even in shape and size, consists of namo rods and are of hollow structures are synthesized. The average diameter of the prepared phosphoric acid microspheres ranges from 1.3 microns to 2.5 microns, and the prepared phosphoric acid microspheres are expected to be widely applied in the fields of photocatalysis, lithium ion batteries and the like.