The invention belongs to the technical field of potato staple food processing, and discloses a potato coarse cereal pellet pancake based on fresh potato juice and a preparation method thereof. The method sequentially performs the following steps: selecting materials, cleaning, juicing of fresh whole potatoes, filtering, mixing, slip casting, auxiliary material spreading, baking, demoulding, cooling and packaging. The method is simple to operate, takes potato pulp as a basic raw material, and saves the steps of peeling, cutting, high-temperature cooking, drying and the like in raw material production, dough kneading, mould shaping and the like in biscuit production. The whole time required for making the potato pellet pancake by the invention is only about 0.5h. Compared with existing processing technologies of potato staple products, the method greatly reduces cost and energy consumption and saves labor and time. Compared with commercially available crispy biscuits, the potato coarse cereal pellet pancake prepared by the method has a unique flavor, comprehensive nutrients, rich dietary fibers, low fat content and obvious advantages.