Conclusions were drawn by analysing the 211Z.1 aluminium alloy direct chill semi-continuous casting sample and hot-extruded sample after T6 heat treatment. The longitudinal grain of the extruded sample is flattened and elongated, the brittle and hard phase is crushed, the unsolidly soluble phase on the grain boundary is broken, and the distribution is uniform. In terms of mechanical properties, the average tensile strength of the cast sample is 476 MPa, and that of the extruded sample is 524 MPa. The tensile of the extruded sample is 48 MPa higher than that of the cast sample, which proves that the strength has been improved to a certain extent. In the terms of corrosion resistance, after etching in NaCl+H2 O2 solution for 6 h, the strength of the cast sample decreases by 38 MPa, and reduction degree is 7.98%, while those of the extruded samples are by 22 MPa and 4.2%. In addition, the elongation decreases by 37.7% and 11.5% respectively. The intergranular corrosion depth of the cast samples is approximately 178 μm, and the grade is 4, while that of the extruded samples is approximately 85 μm and grade 3. The comparative study shows that the mechanical properties, intergranular corrosion resistance and microstructure uniformity of the 211Z.1 aluminium alloy can be improved to some extent and the comprehensive properties will be improved by the hot extrusion process.