Using　the　composite　powders　of　(Na0.5K0.5)NbO3　(NKN)　nano-particles　and　nano-rods　as　stalling　materials,　the　NKN　single　crystals　were　prepared　by　abnormal　gram　growth　(AGG)　method.　The　morphology　evolution　and　the　formation　mechanism　in　the　crystal　growth　process　were　investigated　in　detail.　The　results　revealed　that　the　average　size　and　the　apparent　quantity　of　abnormal　grains　increased　gradually　with　the　increase　of　sintering　temperature　The　biggest　NKN　single　crystals　with　size　of　about　3　mm　were　obtained　at　950　degrees　C　for　2　h　Though　the　nano-particles　and　nano-rods　have　the　same　composition,　the　driving　forces　are　distinctively　different　due　to　the　diversity　of　grain　morphology　The　nano-rods　have　the　large　driving　forces　especially　at　high　sintering　temperature.　which　plays　a　dominant　role　in　facilitating　the　formation　of　NKN　single　crystals　during　AGO　process　(C)　2010　Elsevier　Ltd　All　rights　reserved.