As the installed capacity of wind power generation is increasing continuously,analysis of the impacts on the voltage stability of power system during and after faults is important for the stable operation of power systems. An integral-integral estimate based method is proposed,which is equivalent to the concept of input-to-state stability (ISS),to perform quantitative voltage stability analysis for the power system integrated with doubly fed induction generators (DFIG)-based wind turbine. The advantage of integral-integral estimate is that the fluctuation information of external disturbances on the time scale can be considered. Firstly,according to the quantitative assessment results of subsystems,a system level quantitative stability assessment method based is proposed on small gain theory. Then,the voltage stability of power system integrated with DFIG is analyzed based on the proposed approach. Time-domain simulation on a power system integrated with a DFIG-based wind turbine verifies the accuracy of the proposed method.