A new strategy for the sintering of transparent lanthanum-doped yttrium oxide was presented. This method is the extension of the well-accepted two-step sintering process for the densification of nanomaterials. The samples were firstly sintered at an intermediate temperature T1 (1450°C) in air. Then the temperature decreased quickly to a lower point T2 (900°–1100°C) in air and held for more than 20 h in order to facilitate densification with limited grain growth. Nanocrystalline yttria ceramic with a high relative density was then obtained, which can be further densified at higher temperature T3 (>1700°C) in vacuum. After sintering, transparent yttria doped with 10% lanthanum ceramic was obtained with the grain size around 25 m without annealing. The samples were densified mainly in air at low temperature, it is more easy for operation. The transmittance at 580 nm is 77%, which was equal or better than that from other sintering method for transparent yttria ceramics.