An equivalent heat transfer coefficient between tissue and blood in a porous model is investigated, which is applied to the thermal analysis of a biological tissue in a hyperthermia therapy. This paper applies a finite difference method to solving the tissue temperature distribution using Pennes' bio-heat transfer equation and a two-equation porous model, respectively, and then employs a conjugate gradient method to estimate the equivalent heat transfer coefficient in the two-equation porous model with a known perfusion rate in Pennes' bio-heat transfer equation. The results indicate that the equivalent heat transfer coefficient is not a strong function of the perfusion rate, blood velocity and heating conditions, but is inversely related to the blood vessel diameter. (C) 2008 Elsevier Ltd. All rights reserved.