The microstructure and mechanical properties of Al-21 wt% Si components fabricated by plasma spray forming are analyzed. The microstructure of the plasma spry formed component showed a homogeneous distribution of fine Si particles embedded in the Al matrix. The grain size of α-Al varied between 200 to 500 nm and the size of the Si particles was about 50 to 100 nm in the plasma spray formed component. The room temperature tensile strength of the plasma spray formed component was 215 MPa with 0.5 % elongation, while for cast material, it was 130 MPa. Despite the porosities, the ultra-fine microstructure and homogeneous distribution of Si particles embedded in matrix are the foundation of the increased strength of the plasma spry formed component.