Resin sand is resin as the binder configuration of type (core) sand, old sand regeneration is the maximum removal of the surface of the sand binder film, sand surface (particle size) adjustment, it is very economical to replace the new sand that will be used. The recycling of old sand can save the consumption of new sand and the transportation cost for throwing away old sand, and the recycling of sand is even. The surface is smooth and the heat is hidden. It is beneficial to improve casting quality, especially to reduce the amount of resin added when the old sand is recycled and reduce the cost of resin. It can also reduce environmental pollution caused by discharged waste sand.