Predicting the potential behavior a forest fire is an essential task in fire management which aims to minimize the negative impact of fire on property and society. Many fire spread models were developed. They are either physics-based or empirical models. These mathematical models usually use a set of non-linear equations which are mostly complex and couldn’t easily applied in developing countries like Lebanon. This paper poses a semi-empirical mathematical model referring to the experimental results used in Anderson’s model (1983) and relying on Rothermel’s model (1972). The proposed equation uses parameters of both weather and topography, where wind speed and direction, fuel moisture content and slope coefficient are introduced to obtain the expected spread rate (mile/hour).This proposed model is characterized by its simplicity and thus the possibility of implementation in Lebanon.