The invention discloses an alternating current transmission line inversion method based on a current magnetic field. The method comprises a magnetic field sensor measuring part, a circuit inversion model part and a transmission conductor position inversion algorithm part based on magnetic field intensity. The method has the beneficial effects that the method can be applied to an unmanned aerial vehicle line patrol system, and position and current parameters of a field source, namely a transmission conductor, are inverted according to the magnetic field intensity measured by a magnetic field sensor carried by an unmanned aerial vehicle, and furthermore, the method can be applied to direct current and alternating current transmission systems, so that the intelligent line patrol of the unmanned aerial vehicle can be realized.