The present invention provides a slidable cover mechanism of a paper shredder, wherein an upper cover of the paper shredder is provided with a face cover sliding along an upper surface of the upper cover, two sides at a bottom of the upper cover are provided respectively with a first chute and a second chute, two sides at a bottom of the face cover are provided with guiding pillars, the guiding pillars are disposed respectively in the first chute and the second chute, a first pressing plate and a second pressing plate are connected respectively above the first chute and the second chute on the guiding pillars, an exterior side of the first chute is provided with a micro-switch at a bottom of the upper cover, and an extension arm is provided between a side of the first pressing plate and the micro-switch.
