The invention discloses a single crystal furnace for achieving rapid crystal growth through a chemical heat sink enhanced cooling technology and mainly relates to a reaction device capable of conveying reactants and carrying out a chemical endothermic reaction inside the device. The reaction device is composed of a graphite cylinder and a reaction cylinder, wherein the reaction cylinder is made of an inert material; the reactants are introduced from an inlet, the chemical endothermic reaction is carried out in the reaction cylinder at a high temperature, the temperature on the surface of the reaction device and in a nearby argon gas area thereof is reduced, heat on the crystal surface is rapidly transferred, and incompletely reacted reactants and the reaction product are discharged out of the furnace by an outlet. The single crystal furnace is reasonable in structural design, the reactants can react in the reaction device, and impurities can be prevented from being introduced into the furnace in the reaction process. According to the device disclosed by the invention, the growing crystal is subjected to enhanced cooling by virtue of the chemical endothermic reaction, the heat on the crystal surface is rapidly transferred, and the axial temperature gradient inside the crystal is obviously improved, so that the crystal growth speed is improved, and the aim of reducing the crystal preparation cost is achieved.