A spike mold structure includes a first male mold base having a plurality of male molds and at least one firing pin, and a female mold base having a first fixing board, a second fixing board, a plurality of outer female molds and inner female mold. The second fixing board has at least one sliding rod, and the sliding rod has an actuating block. One surface of the first fixing board has a plurality of convex blocks. A plurality of concave slots are located at the surface of the sliding rod. The thimbles push the actuating block to make the sliding rod slidingly move so that the first fixing board and second fixing board are closely embedded or have a gap. Therefore, there is a displacement between the outer and the inner female mold. The spike mold structure is used to mold a bi-colored spike having increased strength.