The invention relates to a preparation method of a high-efficiency silver catalyst for preparing ethylene oxide through ethylene oxidation with polypeptide as a three-dimensional guiding agent. Duringpreparation, a certain amount of the loaded three-dimensional guiding agent is added, the loaded three-dimensional guiding agent takes polypeptide formed by two or more amino acids as a silver activeingredient and takes cesium and/or rhenium as active auxiliary agents, silver and other inorganic active components are selectively precipitated on the surface of alpha-Al2O3 to form a membrane distributed with uniform bulges. The preparation method can realize the membrane-like distribution of the active component silver and the like in the silver catalyst without too complicated change of a conventional preparation process and mode. The method has the advantages of simple operation, low cost, strong controllability and easy preparation. The prepared silver catalyst has the advantages of good activity, high selectivity, good stability and the like.