The invention provides a bottom corner piece male, a bottom corner piece female and a bottom corner piece. The bottom corner piece comprises the bottom corner piece male and the bottom corner piece female. The bottom corner piece male comprises a top wall and two side walls extending downward from the two sides of the top wall; a clamping and containing cavity is formed between the top wall and the two side walls; and assembling holes are formed in the top wall. The bottom corner piece female comprises a bottom wall, a top wall which is arranged in parallel to the bottom wall in a spaced mode, two side walls which are connected to the two sides of the bottom wall and the top wall separately and two end walls which are connected to the two ends of the bottom wall and the top wall correspondingly; assembling holes are formed in the top wall; and a bolting and fixing hole is formed in the bottom wall. The bottom corner piece female is connected inside the clamping and containing cavity of the bottom corner piece male in a clamped mode. The side walls of the bottom corner piece female are opposite to the side walls of the bottom corner piece male. The top wall of the bottom corner piece female is fixedly connected with the top wall of the bottom corner piece male through the assembling holes in a detachable mode. The bottom corner piece male, the bottom corner piece female and the bottom corner piece can be applied to a semiknocked down (SKD) exchanging case, and the problem that the connection strength of corner positions is weak is solved.