The effect of the cooling rate on the solidification behavior of metal nanoparticles is investigated by molecular dynamics simulation. The structure of molybdenum nanoparticles varies with the cooling rate. That is, single-crystalline, polycrystalline then glassy nanoparticles are obtained as the cooling rate is increased from 2.0 x 10(10) to 1.0 x 10(13) K/s. The solidification point decreases with increasing cooling rate then drops rapidly at a cooling rate on the order of 10(12) K/s. These results are summarized in a continuous cooling transformation (CCT) diagram, in which regions corresponding the liquid, single-crystalline, polycrystalline and glassy structures appear. (C) 2010 Elsevier B.V. All rights reserved.