The invention discloses a production technology for preparing high-purity sorbic acid by melt crystallization. The production technology comprises the following steps of firstly, sending freezing salt water into the bottom part of an outer jacket of a melt crystallization device, enabling the freezing salt water to uniformly flow along the outer wall of the crystallization device in a falling film way, feeding a crude sorbic acid solution into the melt crystallization device, enabling the sorbic acid solution to flow down along the inner wall of the crystallization device in the falling film way, gradually cooling and crystallizing, gradually growing a uniform crystal layer on the heat exchange surface, enabling the concentration of the crystal layer to be higher than the concentration of mixture solution, and enabling impurities to gradually enrich into the mixture solution; then, melting one part of crystal layer by adjusting the hot water temperature through a heat exchanger, and melting and removing the impurities with low melting point in the crystal layer, so as to further purify crystals. The production technology has the advantages that the method and technology are simple, the equipment structure is compact, the falling film type is adopted, the energy is decreased, and the cost and equipment investment are reduced at same time; the purity of a product produced by the melt crystallization device is high.