In this study, we have investigated a new Ag-La alloy contact to p-type GaN for producing high reflectance and low contact resistivity ohmic contacts. A low specific contact resistivity of 5.87×10-5 Ω cm2 and high light reflectance of 85% at 460 nm could be obtained from Ag-La alloy contacts after annealed at 350 oC in air ambient. The formation of lanthanum oxide suppresses the Ag oxidation during annealing process and leads to a good ohmic contact with high reflectance. Additionally, compared with pure Ag contacts, the Ag-La alloy contacts show better thermal stability after a long thermal annealing at 300°C in air ambient.