A combustion gas piston type movable guiding tube netting device includes a capture net (8), a traction head (6), a guiding tube (7), an igniter (3), a main gunpowder (5), a combustion gas generator (1) and a piston (2). The piston and the main gunpowder are placed in the combustion gas generator. The top of the piston contacts with a triangular lug on the base of the guiding tube. The traction head is placed in the guiding tube, and another end of the traction head is tied on one corner of the capture net. When operating, the main gunpowder is ignited by the igniter, the resulting combustion gas pushes the piston to move, the piston pushes the guiding tube to move, and the combustion gas comes into the guiding tube and pushes the traction head to burst out the guiding tube, and the traction head drives the capture net to open. The combustion gas piston type movable guiding tube netting device has a quick expansion speed, and the area of the expansive capture net is big.