The utility model discloses a keyboard protective sleeve which comprises a bottom plate used for placing a keyboard, the periphery of the bottom plate is respectively connected with a first folding part, a second folding part, a third folding part and a fourth folding part, and the first folding part, the second folding part, the third folding part and the fourth folding part are sequentially connected to form a containing cavity for containing the keyboard. The side, away from the bottom plate, of the fourth folding part is further connected with a cover plate, the side, away from the fourth folding part, of the cover plate is further connected with a supporting part, the supporting part comprises a first folding supporting part, a second folding supporting part and a third folding supporting part which are sequentially connected, and the supporting part has a supporting position and a storage position; when the supporting part is located at the supporting position, the first folding supporting part, the second folding supporting part and the third folding supporting part are supported on the outer surface of the cover plate by being rolled and folded outwards, and when the supporting part is located at the storage position, the supporting part is attached to the inner surface of the cover plate. The keyboard is effectively prevented from falling off from the side part of the keyboard protective sleeve, and the structural design is ingenious.