The invention discloses a CO2 gas shielded welding wire feeding device and a usage method thereof, and belongs to the field of CO2 gas shielded welding of the machine building industry. With the CO2 gas shielded welding wire feeding device and the usage method thereof, the problems that welding wires are prone to deforming and damaging equipment in the prior art are solved. The CO2 gas shielded welding wire feeding device structurally comprises a pinch roller (1), a wire feeding roller (2), a rubber ring (3), a CO2 gas shielded welding wire (4), a rotary pressurization handle (5), a pressurization arm (6) and an SUS guide sleeve cap (7). An open groove is formed in the pinch roller (1). An open groove is formed in the wire feeding roller (2). The pinch roller (1) and the wire feeding roller (2) are winded by the rubber ring (3). The pinch roller (1) and the wire feeding roller (2) can be tightly pressed by the pressurization arm (6). The degree of pressing can be adjusted by the rotarypressurization handle (5). The rubber ring (3) of the corresponding model is selected according to the specifications of the wire welding (4) for use to be closely winded around the pinch roller (1)and the wire feeding roller (2); and the CO2 gas shielded welding wire (4) is inserted into the SUS guide sleeve cap (7), and is fastened by the rotary pressurization handle (5). The CO2 gas shieldedwelding wire feeding device is simple in structure, can use welding wires of different specifications, and achieves the purposes of being capable of protecting the welding wires and equipment, convenient for replacement, low in cost and easy to maintain.