A linear slide over-molding fabrication method for producing a linear slide by putting a metal base onto a core in an injection mold and filling a molten plastic in the injection mold to mold guide structures on the metal base for guiding cylindrical rolling elements. The metal base has a track groove for matching with a linear guideway, guide structure attachment portions at two opposite sides of the track groove, and first joint surfaces at two opposite sides relative to the guide structure attachment portions. The core has guide structure forming portions corresponding to the guide structure attachment portions, second joint surfaces respectively facing toward the first joint surfaces with a gap about 0.02 mm˜0.04 mm therebetween. Thus, the applied engineering plastic material can fill up the guide structure forming portions to form a plurality of guide structures on the two opposite sidewalls of the track groove.