There have been many reports on the application of radio-isotope x-ray fluo-rescence analyser to the quantitative determination of various sorts of elements. This paper main-ly describes the frist application of Model 84A86 portable x-ray fluorescence analyser to the -determination of copper content in powder samples, massive core samples and gallery wall samp-les from the Zijinshan copper ore district, Fujian Province, and the economic benefits thus gained.