A preparation method of straight chain dextrin embedded conjugated linoleic acid microcapsules comprises the following steps: dissolving waxy starch in water, heating for gelatinizing, cooling, adding isoamylase for complete debranching, centrifuging, and freeze-drying to obtain straight chain dextrin powder; and dissolving the straight chain dextrin powder, placing the obtained straight chain dextrin solution at a crystallization temperature, dissolving conjugated linoleic acid (CLA) in a preheated anhydrous ethanol solution, adding the obtained CLA solution into the solution, carrying out heat insulation stirring for a certain time, taking out, cooling to room temperature, centrifuging, washing the obtained precipitate by using an anhydrous ethanol/water mixed solution to remove uncompounded CLA, centrifuging, and carrying out vacuum drying on the finally obtained precipitate to obtain a microcapsule embedding material containing the CLA. The method improves the solubility of the straight chain dextrin and CLA compound, the oxidation stability of the CLA and the bioavailability in an aqueous solution, so the problems of low dissolvability of the straight chain starch compound, and easy automatic oxidation and low bioavailability of the CLA are solved, and the microcapsules can be added to functional nutrition reinforcement foods and staple foods as a nutrition reinforcement agent.