Abstract: A STUDY ON MEASURING THE ASH CONTENT OF THE COAL BY FeK_X-RAY COMPENSATON TECHNIQUESMa Yonghe；Yang Dazhan；Luo Xiangdong；Su Hailin Pan Zhikui；Li Guixin；Xiao Duyuan；Chi Xiangqian（Instutute of Technical Physics,Heilong jiang Academy of Sciences,Haerbin 150010） ABSTRACT The effect o0f varying iron concentration on measuring the ash content of the coal and the basictheory of the measuring by compensation for variation in iron concentration in the ash is discussed，The mathematical formula of the measuring has been derived and the regression analysis methed hasbeen established for constants of multivariables function. A measuring device has been complected bymeans of the scintillation detector with balanced filters．Experiment results are discussed.Key words ash content X-ray fluorescence analysis back scattering iron compensation