Solidification microstructure and properties of aluminum alloy impeller produced by centrifugal counter-gravity casting has been investigated. For comparison, vacuum suction casting has also been used. Applying centrifugal force during centrifugal counter-gravity casting was found to have a significant effect on α-Al dendrites, which was fragmented into smaller spherical particles. Furthermore, applying centrifugal force at the early stage of centrifugal counter-gravity casting also improves the filling and feeding capacity during solidification and thereby reduces the formation of defects such as shrinkage porosity and shrinkage cavity. This investigation demonstrates that centrifugal counter-gravity casting is very promising to produce high quality complex thin-walled castings.