The invention provides a hot-pressing fixture for preparing a membrane electrode assembly, which comprises an upper clamp plate (6) and a lower clamp plate (7) mutually laminated, wherein the lamination surface of the lower clamp plate (7) is provided with a groove (8). The groove (8) is matched in shape with the membrane electrode assembly to be prepared, so as to adaptively accommodate the membrane electrode assembly. The invention also provides a method for preparing the membrane electrode assembly. By means of the technical scheme of the invention, sealing frames of the membrane electrode assembly are limited by the groove in the operations of placing, laminating and hot-pressing the membrane electrode assembly. Therefore, on one hand, accurate location of the sealing frames can be guaranteed in the placing operation, and on the other hand, the relative positions of two sealing frames can be prevented from being changed due to the subtle change of the relative positions of two clamp plates in the laminating and hot-pressing operations.