The invention relates to the technical field of auxiliary materials of casting, in particular to a mixture, a riser bush made of the same and a preparation method of the riser bush. The riser bush is prepared through mixing, compression molding and drying and with the following raw materials including, by weight percentage, 19% to 23% of aluminum powder, 8% to 12% of ferric oxide, 8% to 10% of graphite, 17% to 35% of cenospheres, 2% to 4% of cryolite, 20% to 28% of tail slag, 2% to 4% of potassium chlorate, 2% to 3% of potassium nitrate, and binders of the required amount and water of the required amount, wherein the aluminum powder and the ferric oxide serve as the auxiliary exothermic materials, the cenospheres serve as the thermal insulation materials, the cryolite serves as the fluxing agent, the tail slag serves as the aggregate, and potassium chlorate and potassium nitrate serve as the oxidizing agents. Because the riser bush obtained with the formula is low in ignition temperature, ideal in ignition time and long in burning time, and provides sufficient heat, the riser bush is long in begin time of solidification, and has the good feeding effect, and the product quality of steel castings is guaranteed.