Abstract: The series compensation technology for largescale wind power can improve the utilization rate of wind power,but the adoption of the technology could increase the possibility of subsynchronous oscillation of wind turbines. In this paper,the model of 5.0 MW doubly-fed wind turbine via series complementary grid connection is established by using PSCAD,and the mode of subsynchronous oscillation is analyzed by using eigenvalue method, and the influencing factors of subsynchronous oscillation are obtained. Finally,the proposed method is verified with the time domain analysis method and the verification results are found to be consistent with the eigenvalue analysis results.