Abstract: The method of TOPO extraction followed by α-counting has been developed for field determination of uranium in uranium ores. The traditional method of field uranium determination is by spectrometry. The content of uranium using that method is determined by the intensity of the ray, therefore, results have larger errors when uranium and radium are in equilibrium. The method researched by this article combines the nuclear and chemical properties of uranium. The content of the uranium is determined directly by the intensity recorded by an α counter after following dissolution and extraction processes. The detection limit of uranium is 2.41 μg/g. When the content of uranium is about 100 μg/g, the relative standard deviation (RSD) is 5.93%. The determining range of uranium is 7.23 μg/g-n%. The dissolution method requires less reagents, has better dissolving efficiency and less pollution. The extraction method has the advantage and efficiency (＞97%). The equipment is portable so consequently can be used in the field where operation is simple and rapid, with higher precision and accuracy than the traditional method.