The invention relates to a turbofan engine air intake duct anti-icing structure and an anti-icing method. The turbofan engine air intake duct anti-icing structure is characterized by comprising an air-entrainment total pipe of an engine core machine, a collector box connected with the air-entrainment total pipe, several heating branch pipes divided from the collector box, and several anti-icing ring chamber arranged in an anti-icing part of an air intake duct port, branch pipe valves are arranged on the heating branch pipes, anti-icing hot gas is introduced into the air-entrainment total pipe and flows to the collector box, then is optionally distributed to at least a part of the heating branch pipes according to the opening condition from the collector box, then is conveyed to the corresponding anti-icing ring chamber through the heating branch pipe, and is discharged from an air exhaust port of the anti-icing ring chamber.