The invention discloses an alpha-alumina carrier. The carrier comprises a lanthanum element and a silicon element which are uniformly distributed in the carrier, wherein the mass ratio of the lanthanum element to the silicon element in the carrier is (0.1-20):1. Extensive and thorough researches are carried out in the field of silver catalyst and alumina carrier thereof, the lanthanum element and the silicon element are innovatively added, namely added in a bulk phase manner, in the process of preparing the alumina carrier for the silver catalyst, and the silicon element and lanthanum element are contained in the prepared carrier and are uniformly distributed in the carrier, so that specific surface and strength of the carrier can be improved; and when being used for preparing ethylene oxide by means of ethylene oxidation, the silver catalyst prepared by the carrier has a relatively low reaction temperature (relatively high reaction activity) and relatively high selectivity.