A computer enclosure includes a computer panel, an expansion card shield, and a retaining member. The computer panel defines a slot and has a support piece located above the slot. The expansion card shield includes a main piece covering the slot and a resisting piece abutting on the support piece of the computer panel. The retaining member is pivotably attached to the computer panel and includes a main portion and a clasping portion connected to the main portion. The retaining member is capable of rotating to a closed position where the main portion resists against the expansion card shield and the clasping portion is secured to the computer panel, or rotating to an open position where the main portion is disengaged from the expansion card shield and the clasping portion is disengaged from the computer panel.