For describing the cluster phenomenon and its effect on drag force in gas-solid two-phase flow，the paper analyzed theoretically develped a model of gas-solid drag force in Eulerian frame under consideration of cluster effects by using the energy minimization concept.Comparing with the existing models，the new model can describe the interaction between gas phase and particle phase reasonably，and avoid error caused by the inaccurate experiential coefficient.In the numerical simulation of a CFB apparatus，the result of the new model agrees with the experiment data well，so it shows the remarkable advantage or simulation of dense gas-solid two-phase flow.