The invention discloses a simulation and detection method based on the line zero-sequence current in a physical model of the power distribution network, and belongs to the field of power distribution automation of the power system. A present detection method has the problem that large errors tend to occur when the practical load impedance is inconsistent with the capacity of a zero-sequence current transformer. According to the method provided by the invention, a three-phase line and an auxiliary winding are wound around the same annular iron core, and the secondary current value and the measuring precision of a zero-sequence current transformer are greatly improved in a magnetic balance principle.