Abstract: Al₂O₃ fiber was added into the SiO₂ matrix powder, and the Al₂O₃/SiO₂ ceramic core was prepared by hot-pressing method. The effects of Al₂O₃ fiber content on the properties of Al₂O₃/SiO₂ ceramic core were analyzed. The results indicate that the mass fraction of Al₂O₃ fiber has a great influence on the linear shrinkage, bulk density and flexural strength of Al₂O₃ fiber/SiO₂ ceramic core. When the content of Al₂O₃ fiber is more than 1wt%, the linear shrinkage of the Al₂O₃/SiO₂ ceramic core decreases to 0.335%, the volume density of the core decreases, and it is stable at 1.790 g·cm^-3; When the Al₂O₃ fiber mass fraction is 1wt%, the flexural strength of the core reaches the maximum value of 20.48 MPa. The mechanism of Al₂O₃ fiber on the sintering shrinkage of Al₂O₃/SiO₂ ceramic core was analyzed.