因得力於同步輻射高強度且能量連續可調的特性，X光吸收光譜(XAS)現已成為探測各類物質電子及局部原子結構的常用技術。本文將概略描述XAS技術之相關原理與數據的處理步驟，並介紹目前國家同步輻射研究中心之XAS光束線及實驗站設施，最後以一些實例說明其在生命科學中之應用成效。

Thanks to the high intensity and energy tunability of synchrotron radiation, X-ray absorption spectroscopy (XAS) has become a powerful tool for probing the electronic and local atomic structures of various materials. In this article, we briefly introduce the principles and data analysis procedures of XAS. Besides, several XAS beamlines and endstations at National Synchrotron Radiation Research Center are described. Some examples serve to illustrate the applications of XAS in life science.