The invention discloses an apple and pineapple flavor castanea mollissima red bean cake, which is prepared by the following raw materials in parts by weight: 33 parts of cooked castanea mollissima paste, 12 parts of cooked red bean paste, 14 parts of apple, 11 parts of pineapple, 12 parts of wheatmeal, 7 parts of adlay seed powder, 6 parts of peanut powder, 5 parts of jujube powder, 5 parts of walnut powder, 4 parts of pumpkin head, 5 parts of okra, 5 parts of kalimeris, 5 parts of egg, 8 parts of olive oil, 3 parts of fresh butter, 5 parts of white sugar, 1 parts of baking soda and 0.8 part of ammonium bicarbonate. The invention also discloses a preparation method of a sweet potato pear fruity cake. Compared with the prior art, the sweet potato pear fruity cake has the following advantages that cooked sweet potato paste, coked Chinese yam paste, pears and dragon fruits are mixed, so that the dietary fiber and other nutrients are increased. The okra, the pumpkin head and the kalimeris are added, so that the healthcare function of the castanea mollissima cake is improved, the taste is good, the flavor is unique, and the cake is suitable for eating of any people, and particularly suitable foe eating of diabetes patients.