Method for surface modification of alumina carrier, carrier obtained therefrom and application of carrier

The invention relates to a method for surface modification of an alpha-alumina carrier of a silver catalyst used for producing ethylene oxide through ethylene oxidation. The method comprises the following steps: 1) dissolving at least a compound containing aluminum and at least a compound containing silicon in deionized water, and optionally adding at least a compound containing citrate so as to prepare a solution; and 2) placing an initial alpha-Al2O3 carrier in the above-mentioned solution containing Al and Si and carrying out impregnating, then carrying out leaching and drying, and carrying out calcination treatment so as to obtain a composite alumina carrier finally. The invention also relates to a carrier obtained by using the method and application of the carrier.