The method of interference airflow is put forward to solve the problem of H-type wind turbine, lower performance, caused by the small angle of attack. The double-multiple stream-tube model is used for analyzing the influence of the interference airflow to the angle of attack in the speed radios of 5 and 6 respectively. Calculation shows that: Disturbance airflow increases the blade angle of attack, and the growth increases with the increase of the azimuth angle within the two scopes of the interference that is 0o?θ?15o and 345o<θ?360o, but the growth decreases in the scope of azimuth angle between 175o and 185o. In the same scope of interference, as tip speed ratio higher, the growth of blade element angle of attack lower instead; The range of interference to the improved performance in 0o azimuth angle is higher than that is in 180o azimuth angle, in azimuth angle between 0o and 15o, the growth of the blade element torque is higher than that in scopes of 345o<θ?360o, and that is the lowest in the azimuth angle scope 175o?θ?185o. At the same time, the effect rules of interference angle impact on wind turbine performance is analyzed, studies have shown that, increasing the interference angle in 0o and 180o appropriately can improve wind turbine performance and the torque growth of the up-disk is higher than down-disk when the interference angle growth is equal.