A kind of novel blue-emitting chloro-germanate phosphors Ca3GeO4Cl2:Eu2+ have been synthesized via a high temperature solid-state method. Crystal structure of the as-prepared phosphor was discussed from the viewpoint of the doping behaviors of the activators. The luminescence properties and thermal stability studies of Ca3GeO4Cl2:Eu2+ were investigated in detail. Ca3GeO4Cl2:Eu2+ phosphors exhibit broad-band excitation band in the near ultra-violet region and blue emission band peaking at 428 nm, which are both ascribed to 4f-5d transitions of Eu2+ ions. The optimum concentration of Eu2+ in Ca3GeO4Cl2 phosphor was determined to be 3 mol%, and the concentration quenching mechanism was considered to be the dipole–dipole interaction with critical distance Rc = 22.11 Å. Thermal stability studies show that the photoluminescence intensity of Ca3GeO4Cl2:Eu2+ phosphor at 150 oC was 77% of the initial value at room temperature. The activation energy E was calculated to be 0.163 eV suggesting good thermal stability. The variation in lifetime of Ca3GeO4Cl2:Eu2+ phosphor was also discussed to verify different luminescence centers in the lattice.