The invention is related to a computer enclosure. The computer enclosure includes a chassis, an expansion card, and a rotating member. The expansion card includes a shield plate which has a bent end formed thereon. The chassis includes a sidewall. A slot is defined in the sidewall. The sidewall forms a support plate at a side of the slot. The sidewall is capable of accepting the shield plate of the expansion card to shield the slot of the sidewall, and the support plate is configured to accepting the bent end of the expansion card. The rotating member includes an arm. The rotating member is capable of rotating on the sidewall to a locked position. In the locked position, the arm is capable of exerting force on the bent end of the expansion card located on the support plate, and the locked position is capable of securing the expansion card on the sidewall of the chassis.