A sliding hard disk drive mounting hardware includes a sliding box inserted in a recessed chamber on a computer mainframe and releasably locked in place through tenon-and-mortise joints to hold a hard disk drive for permitting the i/o port of the hard disk drive to be electrically connected to the master board of the computer mainframe through an interference elimination circuit board and an interface circuit board. A LED indicator is turned on by means of the control of a control card as the hard disk drive is installed to produce a signal of low potential, or turned off as the hard disk drive is not installed.