A combinative pet cage comprises a front meshed board, a rear meshed board, a left meshed board, a right meshed board, a top meshed board, a bottom meshed board, a plurality of screw parts, and a plurality of connecting parts. The frame of each of the meshed boards is provided with screw holes for the insertion of the screw parts, whereby the meshed boards will be assembles to form a cage body. The top and bottom faces of the frames of the front meshed board and the rear meshed board are further provided with a plurality of insertion holes, whereby two such combinative pet cages can be connected vertically by the connecting parts. A plurality of pet cages can be connected in the same way, and the combined structure thereby formed will be stable.