The invention belongs to the technical field of marine organism chemical engineering and particularly relates to a production method of propylene glycol alginate. The production method of the propylene glycol alginate comprises the following steps: (1), brown algae is taken as a raw material, digesting treatment on the brown algae is performed, and then filtering, calcifying, dewatering and smashing treatments are performed; (2), pelletization treatment is performed on alginic acid obtained; (3), alginic acid particles obtained are washed by an organic solvent; (4), the alginic acid particles are freezed and smashed; (5), esterification reaction is performed; (6), centrifugation is performed; (8), an end product is obtained through drying, pulverizing and packaging. The production method provided by the invention can remarkably reduce the consumption of epoxypropare under the premise of not impacting product quality.