Al
2O
3 fiber was added into the SiO
2 matrix powder, and the Al
2O
3/SiO
2 ceramic core was prepared by hot-pressing method. The effects of Al
2O
3 fiber content on the properties of Al
2O
3/SiO
2 ceramic core were analyzed. The results indicate that the mass fraction of Al
2O
3 fiber has a great influence on the linear shrinkage, bulk density and flexural strength of Al
2O
3 fiber/SiO
2 ceramic core. When the content of Al
2O
3 fiber is more than 1wt%, the linear shrinkage of the Al
2O
3/SiO
2 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 Al
2O
3 fiber mass fraction is 1wt%, the flexural strength of the core reaches the maximum value of 20.48 MPa. The mechanism of Al
2O
3 fiber on the sintering shrinkage of Al
2O
3/SiO
2 ceramic core was analyzed.