To explore the crystallization during the cooling stage in short fiber reinforced composites, a multi-scale model in which macroscopic temperature and microscopic crystal morphology are related with each other is built up. According to this multi-scale model, the algorithm of coupling finite volume method with pixel coloring method is proposed. The finite volume method is used on the coarse grid to calculate the macroscopic temperature and the pixel coloring method is employed on the fine grid to capture the morphology of crystallization. Roles of cooling rate, initial temperature as well as the nucleation rate per unit fiber surface are investigated. To our knowledge this is the first time that a fully coupled multi-scale model and a multi-scale algorithm have been applied to the crystallization of short fiber reinforced composites. (C) 2011 Elsevier Ltd. All rights reserved.