Abstract: The influence of the properties of reclaimed coated sand on the surface quality of alloy steel castings was discussed. By using a new type of pure coated sand to make outer shell cores, the casting defect of poor surface quality of alloy steel turbocharger housing castings was solved, which increased the casting yield of turbocharger housing products, ensured the delivery of the castings, while reducing the production cost and ensuring the stability of batch production of the castings, achieving good.