The invention relates to a preparation method of a ladder boss printing plate. The method comprises the steps of: prepressing a prepreg on a second core plate; cutting along a shape frame of the second core plate to divide the second core plate into a boss plate and an outline plate located on the periphery of the boss plate; removing the prepreg prepressed on the outline plate; according to the plate surface area of the boss plate, windowing a glue-resistance release film, and prepressing the glue-resistance release film on a first core plate in counterpoint; performing counterpoint lamination to the first core plate prepressed with the glue-resistance release film and the second core plate prepressed with the prepreg; and, removing the outline plate and the glue-resistance release film prepressed on the first core plate. By adoption of the preparation method of the ladder boss printing plate, the glue-resistance release film is kept out of the periphery of prepreg when laminating the boss plate and the first core plate, so that the glue is prevented from overflowing when laminating the prepreg located between the boss plate and the first core plate. Thus, the ladder bottom is smooth; and the welding performance of the bonding pad is higher.