An electronic device includes a case having a vent defining a plurality of holes. The electronic device further includes an adjusting plate movably mounted on the case and aligning with the vent, and the adjusting plate defines a plurality of holes. A plurality of vent regions are defined on the vent, at least one hollow region and at least one tangible region are defined on the adjusting plate. The adjusting plate is movable relative to the vent such that the plurality of the holes of the adjusting plate aligns with, or the adjusting plate partially blocks or totally blocks, the plurality of holes of the vent.