The invention relates to an overhead line field-line coupling modeling method based on a non-uniform excitation electric field. The method comprises the following steps: establishing coordinates; building an overhead line model based on line parameters, and acquiring an overhead line telegraph equation; fitting field intensity amplitudes of the non-uniform excitation electric field, and generating a function expression of field intensity amplitudes and distance x; substituting into the overhead line telegraph equation, and acquiring cable response under inhomogeneous wave incidence. The method not only improves the calculation accuracy, but also greatly improves the calculation efficiency.