The invention relates to a method adopting 157nm deep ultraviolet laser as a light source for preparing a field emission cathode. The method can ideally control the state of distribution of cathodes of a field emission display and the shape and the sharpness of a pointed cone of each cathode, thereby increasing the density and the emission uniformity of cathode emission current. The technical scheme is as follows: under vacuum environment, silicon materials are irradiated by the 157nm deep ultraviolet laser matched with corresponding masking techniques so as to form a corresponding inverted-cone structure, and organic polymer materials are injected inside; and after consolidation and formation, the silicon materials are removed, thereby obtaining a folding and soft tip cone-array substrate. The method can accurately control technological processes, has low power consumption and high brightness, the prepared cathode is ultra-thin, and the state of distribution of the cathodes of the field emission display and the shape and the sharpness of the pointed cone of each cathode can be ideally controlled.