In this study a mathematical model has been developed to simulate two dimensional fluidized beds with uniform fluidization. The model consists of two sub models for hydrodynamic and thermal behavior of fluidized beds on which a FORTRAN program entitled (NEWFLUIDIZED) is devolved .The program is used to predict the volume fraction of gas and particle phases, the velocity of the two phases, the gas pressure and the temperature distribution for two phases. Also the program calculates the heat transfer coefficient. Besides that, the program predicts the fluidized bed stability and determines the optimum input gas velocity for fluidized beds to achieve the best thermal behavior. The hydrodynamic model is verified by comparing its results with the computational fluid dynamic code MFIX [1]. The thermal model was tested and compared to the available previous experimental correlations. The model results show good agreement with MFIX results and the thermal model of the present work confirms Zenz [2] and Gunn [3] equations.