Abstract: Particle analysis of uranium containing particles plays a significant role in nuclear safeguards. Standard particles of known isotopic composition and suitable size are needed to insure the precision and the accuracy of the measurement for uranium isotopic ratios in single particles. These particles can be obtained by dissolving standard reference uranium materials, nebulizing the solution into droplets of proper diameter and collecting the particles after the desolvation and calcination of the droplets. A set of instruments based on a vibrating orifice aerosol generator was set up. It was observed by SEM that the monodisperse uranium oxide particles are nearly spherical. The composition of the particles, measured by energy dispersive X-ray spectrum, is only uranium and oxide. Their diameter distributions evidence the presence of several populations, the major showing a distribution with a maximum centers at 1.1 μm. The other populations are mainly due to the breaking up and aggregation of the droplets. The isotope ratio of uranium measured by SIMS is in good agreement with the reference values. SIMS analysis demonstrates that the abundance of uranium in these particles matches nominal value. The fluctuation of correction factors between different particles are relatively small and the sizes of particles can meet the demand of measurement. Therefore, these particles can satisfy the requirement in our measurement.