The invention relates to an infiltration method for preparing a single-domain Gd-Ba-Cu-O superconducting block. The method comprises the following steps: preparing pioneer powder of Gd2BaCuO5 and liquid-phase source powder; suppressing a pioneer block of Gd2BaCuO5 and a liquid-phase block; compressing a supporting block; assembling the pioneer block; infiltrating and growing the single-domain Gd-Ba-Cu-O block; and carrying out oxygen permeation treatment. The invention adopts a top seed crystal permeation growth method and enables the whole permeation growth process to only need two kinds of pioneer powder of Gd2BaCuO5 and BaCuO2 by changing components of the liquid-phase source powder used by the liquid-phase block, thereby simplifying the experimental links, shortening the experimental period, decreasing the experimental cost, saving power resources and improving the efficiency. The method adopts Yb2O3 to prepare the supporting block which stably supports the two blocks in a slow cold growth process of the Gd-Ba-Cu-O block to prevent liquid-phase loss; and the method not only can be used for preparing the Gd-Ba-Cu-O superconducting block but also can be used for preparing high-temperature superconducting blocks of other series, such as Y, Sm, Nd, Eu, and the like.