In this study, a model capable of predicting the steady state performance of a fluidized bed straw gasifier at a wide range of operating conditions was developed. The model was based on the homogeneous equilibrium theory, material and energy balances, and the two-phase theory of gas-solid fluidized beds. The three equilibrium reactions (water-gas shift, methanation and oxidation reactions) were used in the model. The model is kinetic fi ee and capable of predicting the reactor temperature and composition, higher heating value, and production rate of the produced gas.