A protective case for a portable electronic device includes a base and a cover. The base has an accommodation portion. One side of the base is formed with a connecting groove. The cover includes an inner decorative part, an outer decorative part, and a transparent plate. The inner decorative part has an inner side frame with an inner connecting piece. The outer decorative part has with an outer connecting piece. The inner and outer decorative parts are attached to two sides of the base, respectively. The transparent plate is disposed between the inner decorative part and the outer decorative part. The transparent plate has a protruding portion extending from the periphery of the transparent plate. The protruding portion is thinner than the transparent plate to form a stepped side. The inner side frame of the inner decorative part is attached to the stepped side of the protruding portion.