To investigate the effect rule of aluminum powder on the explosion field pressure and temperature of aluminized explosive in vacuum environment, the explosion field pressure and temperature of four kinds of aluminized explosives containing spherical aluminum powder with particle size of 4, 13 μm and 28 μm and slice aluminum powder with particle size of 130 μm were measured in a sealed explosion chamber. Results show that the significance of aluminum powder on the explosion field pressure of aluminized explosive reduces in the order of 13 μm spherical aluminum >4 μm spherical aluminum >28 μm spherical aluminum >130 μm slice aluminum and the effect of aluminum powder on the explosion field temperature of aluminized explosive raises in the order of 28 μm spherical aluminum >130 μm slice aluminum >4 μm spherical aluminum >13 μm spherical aluminum, revealing that the effect of aluminum powder on the explosion field pressure and temperature has no correlation with particle size of aluminum powder.