The microstructures, compression and corrosion behaviors of the as-cast AlxCrFeMn0.8Ni2.1high-entropy alloys (0 ≤ x ≤ 2.3)were investigated in this paper. It was found that the crystal structure changed from initial dual FCC structure to mixed FCCand BCC structure, then to BCC structure as the increasing of Al content. Al0.8CrFeMn0.8Ni2.1alloy exhibited a typicalspinodal structure consisting of alternating two phases microstructure. Moreover, sunflower-like microstructure was obtainedin the as-cast AlxCrFeMn0.8Ni2.1alloys (1.0 ≤ x ≤ 2.0). With the increasing of Al, the macrohardness increased while the plasticitydecreased in the alloys. The addition of an appropriate amount of Al could improve the compressive fracture strengthof the alloys. In addition, the corrosion resistance deteriorated slightly with the increasing of Al in 1 mol/L NaCl solution.