Abstract: An analytical method for low concentration uranium and plutonium was developed. In this method uranium and plutonium sampled from nuclear fuel reprocessing solutions were simultaneously determined by highly oriented pyrolytic graphite (HOPG) pre-diffraction EDXRF. The matrix influence was corrected by plotting I(U)/Ic(Ag)-ρ(U) and I(Pu)/Ic(Ag)-ρ(Pu) instead of I(U)-m(U) and I(Pu)-m(Pu) as their calibration curves where I(Ag) was the intensity of a scattered line from a silver target. The square of correlation coefficient (r²) is better than 0.9990 for both uranium and plutonium in the concentration range 2.00-1000.00 mg/L. The experimental measurement results show that the precision (s_r) is better than 5% for both uranium and plutonium, and the relative error is less than 3.0% and 4.0% for uranium and plutonium, respectively.