A novel 3d transition metal high-entropy alloy (3d tm HEA), Al0.5CrCuFeV, was prepared by vacuum arc-melting. Its phase components, microstructure, and compressive properties in the as-cast and annealed states were investigated. The results indicated that the microstructure consisted of primary BCC dendrites with a volume fraction of 88% and minor FCC Cu-enriched regions that formed a net-like framework. In both the as-cast and annealed states, the alloy possessed a balance between its yield strength (1360 MPa) and ductility (9.1% elongation). Annealing modified the elemental distribution without changing the mechanical properties, implying that the microstructure morphology, not the elemental distribution, played a dominant role in determining the macro-mechanical behavior.