In order to study the influence of coated sand thickness on casting residual stress and solidification cooling process，the casting residual stress of ZL205A aluminum alloy cylinder with different sand thickness was measured by drilling method，and the solidification curves were collected.The paper has carried out finite element simulation of coated sand casting processes for ZL205A aluminum alloy specimen by adopting Von Mises mold and Mohr-Coulomb mold.The results show that the residual stress of castings can be reduced by about 62%,when the sand thickness reaches 7 mm.The residual stress changes a little with the sustained increasing of sand thickness.To provide a reliable process reference，the relationship between sand thickness and solidification cooling rate，grain size and eutectic temperature was established by analyzing and comparing the temperature curve measured in coated sand casting process.The simulation results show that the calculated results of the two models are basically consistent with the experimental trend.But we also need to take into account the applicability of the two models under different sand thickness.