Abstract: In order to eliminate the shrinkage cavity and shrinkage porosity defects in the casting process of an aluminum alloy brake caliper, numerical simulation methods were used to analyze the temperature field and shrinkage porosity during the solidification process of low-pressure casting of the aluminum alloy brake caliper. The position distribution and size of the shrinkage cavity and shrinkage porosity defects were predicted, and the formation reasons were analyzed. On this basis, the process optimization was carried out by optimizing gate, adjusting mould structure and temperature, adopting local heat preservation and adding cooling. The results show that there is no shrinkage cavity and shrinkage porosity in the optimized castings, which improves the quality of the castings.