Based on laser-induced breakdown spectroscopy, a short pulse laser is used to excite Al2O3 (content of 99%) ceramic to produce ceramic plasma. The plasma emission spectrum is collected, and 33 spectral lines of AlO radical B2+X2+ transition are obtained. The time-resolved AlO radical spectrum and its relationship with laser pulse energy are investigated. The results show that the emission spectrum of AlO radical appears later and lasts longer than those of Al atom and Al ion. With the increase of the laser pulse energy, the spectral intensity of AlO radical decreases and the time when the maximum spectral intensity appears moves backward. Finally, the ceramic plasma produced in air is compared with that produced in Ar environment. The results prove that the formation of AlO radical spectrum has an important relationship with O2 in air.