Abstract: A method for the determination of trace selenium in soil samples by hydride generationatomic fluorescence spectrometry with baking separation was proposed in this paper. Samples were semi-melted by baking with Na2CO3 and ZnO mixture as a baking agent and the melt was then dissolved with boiling water, the transition elements including Cu, Co, Ni, etc. were separated. Trace selenium in the soil sample solution was then determined by hydride generation atomic fluorescence spectrometry. The operation conditions for the determination were optimized by the orthogonal experiments. The interferences from the coexistent elements of Cu, Ni, Fe, Al, Pb, Au, As, Bi, Sb and Pt on the selenium determination were studied. The detection limit of the method for selenium is 0.0135 μg/g and the recovery is 87.0%~123.0%. The method has been applied to the determination of trace selenium in National Standard Reference Materials and the results are in agreement with certified values. 