A simplified model is introduced to predict the size-dependent undercooling, superheating and melting entropy of indium nanocrystal. The conditions of melting thermodynamics increasing or decreasing with the reduced size have been discussed. The minimum critical size and the lowest melting temperature of free indium nanoparticles are calculated, and the differences of the degressive slope of melting temperature between embedded indium nanocrystals with incoherent interface and free indium nanocrystals are discussed as well. It is found that the model predictions agree well with the experiments of indium nanocrystals. (c) 2005 Elsevier B.V. All rights reserved.