Abstract: The effects of extrusion ratio on microstructure and tensile properties of Al-0.7Fe-0.2Cu-0.02B aluminum alloy bars which were produced by hot extrusion were studied. The results show that dynamic recrystallization occurred during hot extrusion, with the increase of the extrusion ratio, the recrystallization grains became smaller and more uniform distribution. After extrusion, the second phase Al6Fe transformed into Al3Fe, and the Al3Fe phase became small gradually and gathered at the grain boundaries with the increase of extrusion ratio. With the increase of extrusion ratio from 6 to 28,the tensile strength increased from 106.53 MPa to 122.67 MPa and the yield strength increased from 78.88 MPa to 84.65 MPa. The relationship between yield strength σ0.2 and mean grains size d of the extruded alloy obtained by data fitting was σ0.2=63.8+77d-1/2.