An embodiment of the invention discloses a control method and system of a wind turbine. The method includes acquiring the air density of the current environment; adjusting control parameters of the wind turbine according to the air density of the current environment to allow the wind turbine to optimally operate in the current environment. According to the embodiment of the method, the air density of the current environment is measured, the control parameters, such as the electromagnetic torque of a generator, the generator speed, cut-in and cut-out wind speed, torque control determination, a limiting value for starting and shutdown yaw control and pitch control determination, can be calculated during a unit operating in real time, and control strategies can be optimized according to operating situation of the wind turbine, so that the wind turbine can operate at an optimal state in various climates, and the range of generating operation of the wind turbine can be expanded greatly.