Disclosed is a method of adaptively adjusting lift and drag on an airfoil-shaped sail. The method includes: (1) mounting at least one airfoil-shaped sail body having an airfoil-shaped cross section; (2) defining a Y-shaped air jet channel in the airfoil-shaped sail body; (3) arranging a flow regulating gate in the Y-shaped air jet channel; (4) adjusting the flow regulating gate to automatically adjust the gate opening extent and the cross section opening or closing extent in response to an oncoming flow with a varying direction and speed, to regulate the airflow within the air jet channel and accordingly change the angle of attack, so that the lift and drag on the sail body can be automatically adjusted as the wind speed changes. Further disclosed are an airfoil-shaped sail implementing the above method as well as a vertical-axis wind turbine employing the airfoil-shaped sail.