The invention discloses a 3D printing rapid forming method of a food. The method comprises the following steps: 1, fully mixing food materials with a forming agent A, wherein the food materials are solid materials, and are rubbed in advance; 2, placing the obtained food material and forming agent A mixture in the extruding cylinder of the nozzle of a 3D printer, and placing a forming B in the spray cylinders of the 3D printer; and 3, starting the 3D printer, automatically extruding the food material and forming agent A mixture to the movable working platform of the 3D printer by the 3D printer according to model layering information to prepare an intermediate formed material, uniformly spraying the forming agent B on the extruded intermediate formed material by the spray cylinders of the 3D printer to carry out chemical reaction solidification on the intermediate formed material and the forming agent B in order to form a hard and thin layer on the surface of the food materials, downward moving the working platform for a distance of one layer after one-layer solidification is completed, continuously printing, and repeating spraying, solidifying, moving and printing processes until the required 3D entity food is finally stacked. The method can be applied in the field of food processing, allows many materials to be applied, is not restricted by materials, and is independent of temperature difference solidifying formation.