With the fast development of wind power generation， how to connect wind farms to power grids becomes a crucial problem. This paper studies the connection methods and the control strategy of wind farms using DFIG wind turbines. Compared to AC and current source converter based HVDC（CSC-HVDC） transmission， VSC-HVDC transmission technology has its unique advantages in connecting wind farms to the grids. Based on the d-q decoupling control method， the control scheme of DFIG and VSC-HVDC converter is studied. In order to verify the feasibility of the control scheme， simulations are carried on the platform of PSCAD/EMTDC. The results show the validity of proposed connection method and control strategy.