A lead frame assembly includes two lead frames detachably coupled to each other. Each lead frame has an insulating frame, several signal terminals fixed on the insulating frame, and a ground terminal fixed on the insulating frame. One of the ground terminals has a shielding sheet and several groups of elastic arms, and the shielding sheet and the elastic arms are protruding from the corresponding insulating frame; another ground terminal has several shielding portions protruding from the corresponding insulating frame. The ground terminals are contact with each other along a shielding direction, and the groups of elastic arms are respectively abutted against the shielding portions. In a space, which is surroundingly defined by the contour of the shielding sheet extending along the shielding direction, the shielding direction passes through at least one of the shielding sheet, the elastic arms, and the shielding portions.