Samples of Er3+/Yb3+ co-doped ZrO2-Al2O3 powders were prepared by solid-state reaction. The upconversion luminescence spectrum excited by 980 nm laser light suggests that there exit three main emission bands: one red emission band centered at 654 nm and two green emission bands centered at 545 and 525nm, corresponding to Er3+ ions transitions of 4F9/2→4I15/2, 4S3/2→4I15/2 and 2H11/2→4I15/2, respectively. The emission band centered at 654 nm is much stronger than the other two. The upconversion mechanisms are discussed and it is found that both red emission and green emissions are two-photon processes. It can be seen from the XRD spectra that zirconia (ZrO2) mainly exists as a cubic phase,while Al3+ is implanted into the ZrO2 lattice, producing the ZrO1.87. The solid solution towers the site symmetry of the lattices in ZrO2 crystals, which promotes the upconversion efficiency.