The spray pyrolysis process was applied to prepare oxynitride phosphor (SrSi2O2-delta N2+2/3 delta:Eu2+), and the luminescence properties were investigated. The prepared particles had a green emission and good excitation characteristics in the region of 400-450 nm. The SrSi2O2-delta N2+2/3 delta:Eu2+ particles had an oxygen-rich phase (delta approximate to 0). On the basis of the concentration quenching data, the dipole-dipole interaction was dominantly involved in the energy transfer between the Eu2+ ions, and the critical distance was determined to be about 15.1 A. The oxynitride phosphor with a fine size and good luminescent properties could be successfully prepared by the spray pyrolysis. (C) 2008 The Electrochemical Society.