The invention discloses an improved contact box for a high-voltage switchgear, which comprises an insulator. The insulator of a mounting flange is formed by outward protrusion of the edge of an opening, and the mounting flange is provided with four fixed mounting screw holes. The closed ends of the screw holes are wrapped with an insulating layer. The rest of the insulator forms a cylinder. The top wall of an inner chamber of the cylinder is provided with a static contact mounting insert, and the position adjacent to the top wall is provided with a radial trough. The opening directions of the four fixed mounting screw holes are positioned on an inner plane of the mounting flange, one end of the static contact mounting insert is 6 to 8 mm higher than the top wall plane, and the lapping edge of the mounting flange is provided with lapping steps. The external wall of the cylinder in transition to the inner plane of the mounting flange is provided with an annular semicircular groove, and the inside of the groove is provided with a semiconductor rubber ring or coated with semiconductor paint. The contact box has excellent insulation property, can effectively prevent a breaker from being stroke, and the insulator from being electrically aged quickly, and can prolong the service life of the insulator, thereby ensuring the safe and continuous operation of the high-voltage switchgear.