The invention provides a purple sweet potato colocasia esculenta glutinous rice cake, and a preparation method thereof, and belongs to the technical field of food processing. The purple sweet potato colocasia esculenta glutinous rice cake is prepared from purple sweet potato, colocasia esculenta, glutinous rice flour, and additives; the additives comprise peanut, apricot kernel, black sesame, walnut, bean, lotus seed, and dried clausena excavata fruit peel. The preparation method comprises following steps: 1, the above additives are mixed to be uniform, and are smashed so as to obtain a slurry; 2, fresh wild purple sweet potato and colocasia esculenta are steamed and cooled in a pot, and are smashed into smashed purple sweet potato and smashed colocasia esculenta; 3, smashed purple sweet potato and smashed colocasia esculenta are mixed with glutinous rice flour, and then are uniformly mixed with the slurry obtained in the step 1 and white granulated sugar, and an obtained mixture is made into small ball via kneading; and 4, the small ball are packaged with fresh leaves, and are subjected to steaming so as to obtain purple sweet potato colocasia esculenta glutinous rice cake. The purple sweet potato colocasia esculenta glutinous rice cake is capable of improving brain power, improving studying capacity and memory; all the additives are smashed into the slurry via wet grinding; the preparation method is simple, and is convenient to realize; the obtained purple sweet potato colocasia esculenta glutinous rice cake is thick in fragrance, and is suitable for eating at home.