Novel melilite-type Ca2Ga2SiO7:Eu3+ red emitting phosphors with different Eu3+ contents were synthesized via high-temperature solid-state reaction. The crystal structure, optical absorption, and photoluminescence properties were investigated, while density functional theory calculations were performed on the host lattice. The excitation spectra indicate that phosphors can be effectively excited by near-UV light for a potential application in white-light-emitting diodes. Because of the abnormally high intensity emission at about 700 nm arising from the D-5(0) -> F-7(4) transition of Eu3+, the phosphors Ca2Ga2SiO7:Eu3+ show a deep-red emission with chromaticity coordinates (0.639, 0.358).