A hard disk drive case mounting structure includes a case formed of a top cover shell and a bottom holder shell, an electronic system accommodated in the case, and fasteners each including a female fastening component having an annular head press-fitted in one respective vertical mounting hole at the top cover shell of the case and a split tube-like mating connection socket downwardly extended from the annular head, and a male fastening component having a flat circular head press-fitted into one respective vertical mounting hole at the bottom holder shell of the case and a retaining shank extended from the flat circular head and inserted through one respective mounting through hole at a flat frame member of the electronic system and then fastened to the split tube-like mating connection socket of the female fastening component by means of a hook block.