Abstract: A rapid on-line separation and preconcentration method for the determination of uranium in soil was developed by flow injection multi-collector inductively coupled plasma mass spectrometry(FI-MC-ICP-MS) using ²³³U as spike for the isotope dilution analysis. The on-line separation was based on uranium adsorption on UTEVA resin. The absorbed uranium was eluted with 0.2 mol•L^-1 HCl and directly introduced into MC-ICP-MS for measuring uranium isotopes. The method was examined by determining the uranium in soil standard reference materials. The results are in good agreement with the certified values. The limits of detection of ²³⁸U and ²³⁵U are 5.4×10^-9 g and 5.7×10^-11g.