A line control device of an earphone includes an upper cover; a middle cover being detachably and fixedly connected to the upper cover, wherein, an arranging space for arranging a control panel is enclosed between the upper cover and the middle cover; and a lower cover being fixedly connected to the middle cover, wherein, shielding parts are formed on the edges at both sides of the middle cover, and the shielding parts are used for sealing the gaps between the upper cover and the lower cover.