Every simulation of the heat transfer process is based on a given morphology of polymer and gas phase. To measure the effect of every phase in total heat transfer one needs to obtain a simple approximation of the foam morphology. It is necessary to consider every phase separately and simulate the heat transfer process between those phases. In order to reach an accurate simulation of heat transfer process in polystyrene foam in this study, mathematical models for distribution of bubbles in foam media are presented. This effort is aimed to calculate the total heat transfer conductivity of the foam body using various novel mathematic approximations about the morphology of the bubble distribution. The experimental data are compared to the model predictions as well as the predictions of the other models presented by the other researchers in the references. Existing models which are used to simplify the geometry of bubbles contain assumptions which lead to noticeable error. In the present model, an effort has been made to present a real simulation of bubble shapes and distributions. In the present research, four different samples were made by polystyrene and different amount of blowing agent. The samples then were molded to make 65x65x2 mm sheets. The densities of the sheets were measured to figure out the porosity of each specimen. In the next step the thermal conductivity of the sheets were measured using a test set up prepared in our lab. Those samples then were cut and their cross sections were studied using SEM method. The bubble sizes and distributions are modeled to have a real case. That information was used in the next step to develop a mathematical model to predict the random distribution of the bubbles in order to achieve an accurate estimation of the thermal conductivity of the samples. The model predictions were compared to the experimental data and the results obtained using other models presented in the references by the other researchers.