The invention relates to a purple sweet potato solid beverage and a preparation method thereof. The purple sweet potato solid beverage comprises the following components in parts by weight: 25-40 parts of purple sweet potato superfine powder, 5-10 parts of red data superfine powder or hawthorn superfine powder, 40-50 parts of white sugar, and 1-2 parts of skimmed milk powder or whole milk powder,wherein the average particle size of the purple sweet potato superfine powder is 10-20 mu m, and the particle size of the red date superfine powder or the hawthorn superfine powder is 20-30 mu m. According to the invention, the purple sweet potato solid beverage is prepared by mixing the superfine powder obtained through crushing raw materials by using an ultramicro-technique and has the characteristics of good sour and sweet taste and intense fragrance, and a preparation process is simple and is easy to operate and process.