The invention provides a transmission line iteration-based solving method for a 2D axial symmetric nonlinear magnetostatic field model. The method comprises the steps of performing coarse network division and fine network division on a solving domain; adding a corresponding transmission line between a nonlinear element and a linear network; and performing solving on a circuit through an incidence stage and a reflection stage of multi-time iteration to obtain a magnetic potential cloud chart in a 2D axial symmetric nonlinear magnetostatic field. Compared with an existing Newton iteration method, the method has a very great advantage in solving time and has a wide application prospect.