Machining clamp stable in clamping

The utility model relates to the technical field of machining fixtures, and discloses a stable clamping machining fixture which comprises a fixed box and a positioning disc, the bottom of the fixed box is slidably connected with a movable box, the middle of the interior of the movable box is rotatably connected with a gear, the two sides of the gear are connected with racks in a meshed mode, and fixing bolts penetrate through the middles of the racks. The bottom end of the fixing bolt penetrates through the moving box, the top end of the fixing bolt is fixedly connected with the inner wall of the moving box, the end, away from the gear, of the rack is fixedly connected with an extension rod, and one end of the extension rod extends out of the moving box; according to the machining clamp stable in clamping, the moving box is slidably connected to the bottom of the fixed box, the gear is fixedly connected to the interior of the moving box, the racks are connected to the two sides of the gear in a meshed mode, t