Abstract: Grazing-exit X-ray fluorescence analysis (GEXRF) is the extension and development of total reflection X-ray fluorescence analysis technology. Its method, characteristics, basic principles and the experimental apparatus that we set up in the lab are presented. Its history and applications in the field of trace and ultra-trace determination and thin layer analysis are briefly described, with special mention of the analysis of light elements by GEXRF with a wavelength-disperion detector.