An electrical connector includes a base having a top face in which contacts are retained. A cover defining a plurality of through holes for receiving pins of a central processing unit is mounted to the base thereby defining an interior space therebetween for accommodating a slide plate. The slide plate has a conductive member corresponding to each of the contacts and is movable to electrically engage each contact with the corresponding pin of the central processing unit. Two elongate recesses are defined in the top face of the cover. Each elongate recess has two end walls forming two opposite inclined faces. Two elongate projections are formed on a bottom face of the cover and are received in the recesses of the base. Each projection has two inclined end faces matingly and guidingly engaging with the end walls of the corresponding recess thereby properly positioning the cover with respect to the base and preventing the cover from sliding with respect to the base during movement of the slide plate.