The invention discloses a method and a system for inhibiting a residue pole ratio in an overhead line frequency domain propagation matrix vector fitting process. The method comprises the following steps: for each element, when a corresponding initial residue pole ratio is greater than a first preset threshold, performing singular value decomposition on a coefficient matrix, and setting a singularvalue of a product of a maximum singular value in a first singular value matrix and a preset precision threshold to be zero to obtain a second singular value matrix; determining an updated coefficientmatrix by using the second singular value matrix, and determining a new residue vector by using a least square method; removing a pole with a value of 0; judging whether the ratio of the residue corresponding to each of the remaining poles to the pole is smaller than a first preset threshold value or not; if so, indicating that the suppression is successful, and determining a frequency domain propagation matrix for expressing each element in a rational mode by utilizing the residual poles and the corresponding residues so as to ensure the stability of time domain simulation; otherwise, indicating that the suppression fails, and carrying out recalculating.