Abstract: In order to improve the safety of bone grinding operation, low temperature spray cooling was proposed to control the bone grinding process. A 3-dimensional bone grinding experimental platform was built, and a 4-mm medical diamond ball grinding head was used to grind the bone surface with a high rotational speed of 60, 000rpm. The magnitude of grinding force is similar for the forward and backward feeding directions. The average grinding power is about 5W when the depth of cut is 0.5mm. A low temperature saline spray (13℃, 400mL/h) was used to transport the spray to the grinding area through nozzles with different positions, and the effect of spray jet direction and feeding direction on grinding temperature was investigated. The results show that the low temperature spray cooling can make the temperature rise of bone grinding lower than 4℃, which is lower than the temperature rise threshold of thermal damage 6℃, however, the spray jet direction has a great influence on the temperature distribution. When the nozzle is located above the grinding tool, it is conducive to backward feed, when it is located in front of the grinding tool, it is conducive to forward feed, and when it is located on the side of the grinding tool, the influence of feeding direction is small. The above research has laid a certain foundation for optimizing the low temperature spray cooling system of bone grinding.