In the present study we carried out a thermodynamic analysis for explosives with micrometer aluminum (Al) powders, and found that the acceleration of Al powders and heat exchange between Al powders and the detonation products may have a significant influence on the detonation velocity. Relying on velocity disequilibrium between the two phases at the C-J plane and heat absorption of inert Al powders in the detonation zone, this paper has introduced a new method to study the detonation velocity of explosives with micrometer Al additives. The method is a closed system of algebraic equations and the detonation velocity can be solved efficiently by numerical codes. The detonation velocities predicted by the new method are in excellent agreement with experimental data of RDX-, HMX-, NM- and TNT-based aluminized explosives, and the heat exchange has been proved significant on the detonation velocity, while the acceleration of Al powders is of little effect.