Ground　by　mechanical　ball　milling　under　certain　conditions,　beta-Ga(2)O(3)　powders　can　transit　to　epsilon-Ga(2)O(3)　ones.　As　starting　materials,Ga(2)O(3)　powders　treated　by　different　methods　are　used　to　prepare　GaN　nanomaterials.　It　is　found　that　the　morphologies　of　GaN　nanomaterials　are　quite　different　due　to　the　phase　transition　of　Ga(2)O(3)　from　beta-Ga(2)O(3)　to　epsilon-Ga(2)O(3).