Abstract: With the increasing scale of wind power and other new energy installations, major wind power countries around the world, IEEE standard associations, and so on have successively formulated wind power negative sequence grid connection standards. To meet the above standards, doubly-fed wind turbines will face problems and challenges: transient synchronous stability, small disturbance stability and positive-negative sequence, and machine-grid side cooperative control. To this end, this paper first introduces the domestic and foreign wind power negative sequence grid connection standards. Then, the problems and challenges faced by doubly-fed wind turbines to meet the negative sequence grid connection standard are analyzed in light of existing research. Further, in response to the problems and challenges, the key technologies for negative sequence control of doubly-fed wind turbines are summarized and compared. Finally, the development prospects of the negative sequence grid connection standard and the key technologies of doubly-fed wind turbines are discussed and overlooked.