Abstract: XRFS determination of 18 elements, including S, Na, Mg, Al, Si, P, Cl, K, Ca, Ba, Ti, V, Cr, Mn, Fe, Ni, Cu and Zn in oil coke with preparation of disc sample by direct pressing of sample powder was proposed in this paper. The sample was powdered to size less than 0.076 mm, dried at 105 ℃ and pressed in a mould under a pressure of 160 MPa to form a disc sample with its thickness less than 4 mm. Interferences due to matrix effects and overlapping of spectral lines were overcome by the method of empirical coefficient and by using Compton scattering line as internal standard. Values of RSD′s (n=11) were found to be less than 8% by analysis of a oil coke sample. The proposed method was used in analyzing a standard sample, giving results in consistency with the certified values.