The invention discloses screw drill auxiliary mounting and demounting equipment for petroleum and natural gas exploitation. The equipment comprises a screw drill and an equipment base, a surface clearing device is arranged at one end of the equipment base, a plurality of transport supporting devices are movably arranged at the inner end of the equipment base, a fixed clamping device is fixedly arranged on the equipment base among the transport supporting devices, and a third air cylinder is fixedly arranged on one side, away from the surface clearing device, of the fixed clamping device. A mounting and demounting device is fixedly arranged at the top end of a movable clamping device which is fixedly connected with a driving end of the third air cylinder. The equipment has advantages that auxiliary mounting and demounting of the screw drill can be realized, and the surface of the screw drill can be cleared before demounting to prevent impurities on the surface of the screw drill in demounting; in the clamping device of the screw drill, a rotary slide seat, a slider and a fixed slide seat form an aperture structure, the screw drill can be clamped and released, and accordingly clamping of screw drills in different specifications can be realized.