A computer enclosure includes a chassis, a cover detachably mounted to the chassis, and a rotary member pivotably attached to the cover. The chassis includes at least one assembly slot defined therein. A sliding member is slidably installed in the cover. At least one hook is formed on the sliding member and engaged in the assembly slot of the chassis. The rotary member is capable of being rotated to drive the sliding member to slide in the cover, thereby disengaging the hook from the assembly slot.