The invention relates to a preparation method of micro powder capecitabine, the method is as follows: adding a capecitabine crude product into ethyl acetate, dissolving by heating, cooling to a condition that capecitabine reaches a saturation state in the ethyl acetate, adding capecitabine seed crystal, and obtaining the micro powder capecitabine by thermal insulation crystallization, cooling, filtration and drying. The micro powder capecitabine prepared by the method is high in purity and uniform in particle size, does not generate static electricity, does not agglomerate, good in fluidity, easy for scale production, can well ensure the quality homogeneity of a preparation, and makes clinical medication safer.