The invention discloses a one-step molding vulcanization technology of a hollow-core rubber product. The one-step molding vulcanization technology comprises the following steps of: step one. preparinga bar material coated with rubber, specifically, the bar material comprises a bar core and a rubber coating layer coating the bar core, and the bar core is made of a phase change material; step two.removing part of both ends of the bar core in a digging manner, then filling the hollow parts of the bar core with rubber compound, and inserting air nozzles in the mixed rubber to obtain a semi-finished product; and step three. putting the semi-finished product in an indirect vulcanizing tank for vulcanization to obtain the hollow core rubber product. According to the one-step molding vulcanization technology, the phase change material is used as the bar core for preparing the bar material coated with the rubber; the phase change material bar core can stably support the rubber coating layer in the molding process, so that the geometric dimensioning of the molded rubber product is ensured; the phase change material bar core is converted into liquid at a high temperature so as to be discharged in the vulcanization process, so that the one-step extrusion molding vulcanization of the hollow rubber product is realized; the geometric dimensioning of the appearance of the prepared hollow core rubber product meets the requirements; the prepared hollow core rubber product has uniform wall thickness; and meanwhile the hidden danger of damage after inflation caused by a mold pressing splicing method is eliminated.