Among multitudinous rod pieces in a tower structure,most rod pieces are secondary,and only small amounts of themarekey components whichare of higher damage probabilityandhave seriousinfluenceon the whole tower structureif they are damaged. Therefore,it is meaningless and also unpractical to make damage identifications on all components in a tower structure.In order to enhance pertinence,a damage identificationmethod, which is based on theanalysisof key components, is put forward in this paper. Inthis method, decrease degrees of the structure system’s reliability caused by the same degree of damage of components are firstly calculated; then, weight coefficients are introduced to measure the relative importance of the various components of the whole structure system, thus the key components can be defined through comparing the values of these weight coefficients. Finally, a damage sensitive feature based on the Wigner-Ville distribution (WVD) of the acceleration signalsunder fluctuating windis derived to damage detectionand localization of these key components, and the relationshipof the damage sensitive feature to mode shapes of the structure is demonstrated.This method is verified through an example of a communication towerat the end of this paper.