A snap-fit type self-locking combined upper cover for a power strip is formed by combining a first upper cover and a second upper cover. The first upper cover is provided with a cover body portion and a connecting portion integrally extending from the cover body portion. The upper surface of the connecting portion is provided with a plurality of snap-fit through holes for snap-fit bases to pass through. The inner wall of the connecting portion is provided with a plurality of connecting snap-fit fasteners which can be snap-fitted to the second upper cover. The second upper cover is a thin-walled shell with an accommodating space, an open bottom and one side open. The inner surface of the upper wall of the second upper cover is provided with a plurality of snap-fit bases projected vertically downward, which can be snap-fitted with the connecting snap-fit fasteners of the inner wall of the connecting portion to form the combined upper cover.