The Ozawa and the modified Avrami models were usually used to describe the nonisothermal crystallization of polymers. A computer simulation approach was adopted to verify the two models. The results show that the Ozawa model is suitable under constant healing and cooling rate conditions, but not the modified Avrami model. Therefore, the Ozawa model was extended to acquiring the linear growth rate of polymer entities. A nonlinear relationship between the logarithm of the rate function and temperature was found. The values of the Avrami exponent are approximate to the designed value and the linear growth rates of the entities obtained are consistent with the designed ones. (C) 2007 Elsevier B.V. All rights reserved.