Recent our progress in low temperature molecular beam epitaxy of magnetic silicide (Fe3Si) on group-IV-semiconductor (Ge) was reviewed. By optimizing beam flux ratio (Fe:Si=3:l) and growth temperature (130 °C), a high quality hybrid structure, i.e., DO3-type Fe3Si on Ge with an atomically flat interface, was achieved. Excellent magnetic properties with a small coercivity (0.8 Oe) and electrical properties with Schottky barrier height of 0.56 eV were obtained. The ratio of the on-current to the off-current of Schottky diode was the order of 104. These results will be a powerful tool to open up group-IV-semiconductor spin-transistors, consisting of Ge channel with high mobility and Fe3Si source/drain for spin-injection.