The invention discloses a preparation method of black potato dumplings. The preparation method comprises the following steps: freezing potatoes, conducting unfreezing, drying the unfrozen potatoes, processing the dried potatoes into powder, mixing the potato powder with buckwheat flour, wheat flour, starch and water, producing dumpling wrappers from the mixture, and making dumplings by filling the dumpling wrappers with stuffing. Compared with the prior art, different from the traditional dumplings made of white wheat flour, the dumplings prepared by the preparation method of black potato dumplings are grey black in color, chewy in mouthfeel, fragrant in smell and rich in nutrients.