The invention discloses a preparation method of a fucoxanthin microcapsule, which belongs to the technical field of food processing. The preparation method comprises the following steps: (1) uniformly mixing palm stearin and fucoxanthin to be used as a core material, and ultrasonically dispersing the core material in a gelatin solution to form uniform emulsion; (2) adding an Arabic gum solution containing a surfactant into the emulsion of the step (1), stirring for 5 to 15 min at constant temperature, adjusting PH to be 3.8 to 4.2 by utilizing acetic acid, and carrying out complex coacervation; (3) lowering the temperature of a system of step (2) to be lower than 10 DEG C, adding a tannic acid solution, and curing microcapsules; and (4) after the microcapsules are precipitated, adding deionized water to wash the microcapsules, repeating for multiple times, and freeze drying to obtain microcapsule powder. The fucoxanthin microcapsule prepared by the invention is uniform in particle size, stable in structure, and unlikely to have the situation such as breaking and leakage of core materials, so that the storage and application of the fucoxanthin can be facilitated.