Ba3Si6O9N4∶Eu2+ phosphors were synthesized by two-step synthesis processes based on high temperature solid phase using BaSiO3 as a precursor. The influence mechanism of the Eu2+ doping concentration to the luminescence properties of Ba3Si6O9N4∶Eu2+ phosphors were mainly investigated. This paper made a comparison between the luminescence properties of Ba3Si6O9N4∶Eu2+ phosphors prepared by two-step processes and solid- state reaction method. The results showed that the Ba3Si6O9N4∶Eu2+ phosphors synthesized by two-step processes had higher purity and higher crystallinity. There exists concentration quenching in Ba3Si6O9N4∶Eu2+ phosphors for both two-step processes and solid-state reaction when the doping concentration x is more than 9%. Both the concentration quenching mechanism of Ba3Si6O9N4∶Eu2+ phosphor prepared by solid-state reaction and two-step processes is electric dipole-dipole interaction. The emission peak of Ba3Si6O9N4∶Eu2+ phosphors (peak 489 nm) prepared by two-step processes had a blue shift compared to the emission peak of Ba3Si6O9N4∶Eu2+ phosphors (peak 512nm) prepared by solid-state reaction. The emission peak of Ba3Si6O9N4∶Eu2+ phosphors prepared by two-step processes relatively close to the theoretical value (480 nm). The spectrum analysis result showed that the element component of Ba3Si6O9N4∶Eu2+ phosphors prepared by two-step processes was closer to the theoretical value, it means that the two-step processes can effectively reduce the lattice defects. The Ba3Si6O9N4∶Eu2+ phosphors synthesized by two-step processes had better thermal stability, which demonstrates to be a highly promising phosphor for white-LED applications.