Effective thermal conductivity is a key parameter to characterize the thermal property of closed-cell aluminum foam. It is of great significance to predict the effective thermal conductivity of closed-cell aluminum foam. In this paper, based on the existing models for effective thermal conductivity of closed-cell aluminum foam, an improved model was proposed. Furthermore, the numerical simulation method was employed to analyze the unsteady heat transfer process of closed-cell aluminum foam. And the effective thermal conductivity was obtained from the distribution of temperature field. The results show that the improved model has higher prediction accuracy compared with Lu model. Besides, the improved model has better applicability and prediction accuracy compared with the three theoretical models from literature.The number of cells in the heat transferdirection has a great influence on the accuracy of the effective thermal conductivity by the numerical simulation method. The accuracy of numerical simulation is the highest when the number of cell holes is enough. Considering cost and accuracy, the improved model has better applicability.