High-quality Al films with an in-plane epitaxial relationship of Al[1−10]//sapphire[1−100] have been epitaxially grown on sapphire substrates by molecular beam epitaxy. The as-grown and ∼200 nm thick Al films prepared at an Al evaporation temperature of 1100 °C were highly crystalline, with a full-width at half-maximum of 180 arcseconds, and had a very smooth surface, with a root mean square roughness of 0.6 nm. There was no interfacial layer between the Al and sapphire. Furthermore, the effect of the Al evaporation temperature on the properties of the as-grown ∼200 nm thick Al films has been studied in detail. This work of achieving high-quality Al films is of great importance for the fabrication of high-performance Al-based devices.