Provided is a protection cover for protecting an optical module. The protection cover installed at an edge of an optical modem in which the optical module is randomly separable without opening a case includes a bottom cover including a hinge and screw coupling hole at one end thereof, a pair of side covers extending toward left and right upper sides from the bottom cover, each of the pair of side covers including a hook at one side thereof, a front cover extending toward a front upper side from the bottom cover, the front cover having a U-shaped front groove, and a pair of top cover horizontally extending from the side covers and the front cover, the pair of top covers having trapezoid-shaped top grooves that are spaced apart from each other.