Abstract: For the 10 GW wind power bases in China,wind-thermal-bundled power transmission by AC/DC system is regarded as one of feasible ways,but the stability characteristic of this kind of transmission systems should be investigated.In the paper,the angle transient stability characteristics were studied in the scenarios with different wind power penetration and DC control modes through simulations,and the interaction among wind power,thermal power and DC systems was discussed.Besides,the effects of the inertias of sending and receiving end systems on the angle transient stability characteristics were studied based on extended equal-area criterion（EEAC）.When the receiving end power grid is equated to an infinite system,the system angle transient stability is improved with the increase of wind power penetration,while the equivalent inertia of the sending end can be comparable to that of the receiving end,there is an optimal wind power penetration with which the system has the highest angle transient stability.