The effects of CuO, TiO2 and B2O3 oxides and nanocrystalline Al2O3+ TiO2 particles on the sintering of Al2O3 glass-ceramics were investigated by X-ray diffraction and scanning electron microscopy. The CuO and TiO2 oxides can effectively facilitate the formation of CuO–Al2O3–TiO2 glass ceramic. The CuO, TiO2 and Al2O3 oxides can form the new phase Cu2Ti4O and CuAl2O4. They wrapped the Al2O3 grains tightly, so the density ceramic was fabricated successfully sintered at 1300°C. Analyzing the fracture surface morphology, the ceramic added CuO, TiO2 oxides shows the mixed mode of intergranular and transgranular fracture. However, after added B2O3 oxides the B2O3-CuO–Al2O3–TiO2 glass ceramic shows the mode of intergranular fracture. The ceramic added nanocrystalline Al2O3 + TiO2 was more density and fine organization. The fracture mode is as same as the ceramic added CuO, TiO2 oxides.