The present invention discloses a method for estimating quality of a link in a broad-band wireless communication system. The method includes: calculating quality indicators of sub-carriers in an input signal of a receiver of the system; clipping the quality indicators of the sub-carriers; and averaging the clipped quality indicators of the sub-carriers to obtain an average value as an estimation result of an effective quality indicator of the link. The present application also discloses an apparatus for estimating quality of a link in a broad-band wireless communication system, an adaption method and apparatus for a link in a broad-band wireless communication system. The methods and apparatus of the present invention can achieve relatively low calculation complexity and high accuracy.