Aimed at the heat transfer problem of composite walls with heat preservation layer, and based on analyzing their compositions and heat transfer characteristics, the mathematic model was set up and the solutions of heat transfer are obtained with the implicit finite difference method. 针对复合保温墙体传热问题,在分析其组成及传热特点的基础上,建立数学模型,并采用有限差分隐式格式求解。