An apparatus of controlling damping force through road frequency classification may include high pass filters configured to perform high-pass filtering of detecting values of wheel vibration input from wheel vibration sensors according to different cutoff frequencies, a main frequency extraction module configured to determine a main frequency of the wheel vibration based on filtered values output from the high pass filters, a maximum amplitude and amplitude ratio extraction module configured to determine a maximum amplitude and an amplitude ratio of the wheel vibration based on the filtered values, a road gripping force control determination module configured to determine whether or not road gripping force is to be controlled based on the determined main frequency and the determined maximum amplitude and amplitude ratio, and a damper control module configured to determine the damping force of dampers of a vehicle based on results of determination and road roughness.