Abstract: In the light of the stability problem resulted from cable distributed parameters in grid connected system,a modified input admittance criterion considering line distributed parameters is proposed. Firstly,a real variable conductance and susceptance model of grid connected system is formed by multi-layer variable substitution and appropriate simplification,and then a simplified hyperbolic function model of grid connected system considering line distribution parameters is established. Secondly,the adaptability of input admittance criterion for stability analysis of grid connected system considering line distribution parameters is verified,and the effect of short-circuit ratio,line length and line parameters on the stability of grid connected system are analyzed. Finally,by comparing the traditional method with Simulink simulation,the correctness and effectiveness of the proposed method are verified.