Abstract: Sodium atomization spray technology is the key technology of disposal for largely radioactive waste sodium. In order to explore the sodium atomization technology, sodium atomization equipment was designed and the dynamic performance of sodium atomization spray was studied. The test was carried out in a sealed container of 2.4 m³. The particle size distribution of sodium droplets at 150 mm from the nozzle was measured by a laser particle analyzer under the argon atmosphere and the test pressures were 0.05, 0.1, and 0.15 MPa. The results show that the median particle size was 567.2, 554.8 and 544.2 μm under the three pressures and the median particle size becomes smaller with the increase of the spray pressure. For all test under different pressures, the group of sodium droplets with the particle size between 464.2-735.6 μm has the largest cumulative distribution, which is more than 50%. A particle size similarity model was established according to the similarity between sodium spray and water spray. The spatial distribution of the sodium spray particle size was simulated by using the known spatial distribution of water spray particle size.