Abstract: Provided are an apparatus and method for controlling a vertical axis wind power generation system that controls the rotation of guide vanes according to wind direction and speed, appropriately controls a direction of wind passing over an impeller, thereby maintaining a rotational speed generating the maximum power, maintains output power of a generator as rated power according to wind direction and speed, and stops the generator when a low or high wind speed outside a setting value range, an error in a structure, a fault in a braking unit, and/or a fault in guide vanes is detected.