4A11 aluminum alloy was prepared using powdermetallurgy method. The influences of forming pressure, sintering process and extruding on the density of aluminum alloy was analyzed. The research shows that the density of aluminum alloy is improved with the increase of pressing force in the certain pressure range, and the density tends to be stable when the pressing force arrives to a certain value. Conventional sintering process cant make aluminum alloy densification, on the contrary，which would lead to drop of the density. Plastic deformation occurred by squeezing, the holes in the material would be filled and at the same time, the oxide in the surface was destroyed by metal flow, which promoted diffusion and transference of material. By this way，the density of aluminum alloy was greatly improved, and the highest density was 97.8%.