The spray pyrolysis process was applied to prepare oxynitride phosphor (SrSi(2)O(2-delta)N(2+2/3 delta):Eu(2+)), 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 SrSi(2)O(2-delta)N(2+2/3 delta):Eu(2+) 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 Eu(2+) 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.