Herein, in order to study the interaction mechanism of mechanical activated energetic composites, molecular dynamics simulation was carried out to calculate the binding energy and the interaction mode of PTFE with different crystalline surfaces of Al and Al2O3. Then the mechanical activated energetic composites were prepared, the microscopic morphology and the surface element content of Al-PTFE composites before and after mechanical activation have been studied. At last, the reactivity was tested. The results show that the adsorption of PTFE on the (0 0 1), (0 1 0) and (1 0 0) surface of Al2O3 and Al is stable. PTFE interacts with Al2O3 mainly via electrostatic force, and PTFE interacts with Al mainly via Van der Waals' force. After 40min ball milling, Al and PTFE melt into a composite aggregate, the adsorption of PTFE on the surface of Al and Al2O3 is stable, the experimental results are in good agreement with the simulation results. Mechanical activation can remarkably reduce the diffusion distance, improve the reaction activity and the detonation velocity of Al-PTFE composites. [GRAPHICS]