The invention discloses a method for preparing yttrium barium copper oxide powder with uniform particle size and belongs to the technical field of preparation of yttrium barium copper oxide powder. The method comprises the following steps: mixing and ball-milling Y2O3, BaCO3 and CuO, calcining and grinding with nano calcium carbonate and the like to obtain precursor gel for standby; taking Kaolin powder and mixing with deionized water to prepare a blank body; exposing to the sun, glazing and putting the standby precursor gel into the glazed blank body; firing, freezing, freezing inside yttrium barium copper oxide, pressing, mixing and ball-milling with absolute ethyl alcohol, performing ultrasonic dispersion and filtering to obtain a filter cake; drying to prepare the yttrium barium copper oxide powder with uniform particle size. The method disclosed by the invention has the benefits that the preparation steps are simple, repeated sintering is not required, and the obtained product is good in uniformity; the uniformity of chemical components in the preparation process is easy to control, and the product particle size is uniform.