A protective case comprises a body, a camera-exposing cutout, a detachable lens cover, and an earphone jack fastener. The camera-exposing cutout is provided at an edge of the body for exposing the camera lens of the mobile device. The detachable lens cover comprises a slide cover and a plug-in cover, and the slide-cover portion is slid into and along the two side edge portions of the camera-exposing cutout and cover the camera lens, and the plug-in cover is plugged in to the camera-exposing cutout perpendicularly to a surface of the body and cover the camera lens. The earphone jack fastener has a first end connected to the detachable lens cover and a second end configured to be plucked into and held in an earphone jack of the mobile device.