Through　adjusting　the　pH　of　the　silver　ammonia　solution　(Ag(NH3)(2)OH),　different　microstructure　of　silver　phosphate　(Ag3PO4)　was　prepared　via　simple　precipitation　method.　The　effect　of　pH　on　the　microstructure　and　photocatalytic　properties　was　studied.　Preliminary　results　indicate　that　the　pH　of　silver　ammonia　solution　played　a　key　role　in　crystal　growth　and　microstructure　of　Ag3PO4.　When　the　pH　is　9,　the　preferential　crystal　growth　of　the　Ag3PO4　oriented　along　the　(110)　crystal　surface.　Thus,　the　cubic　Ag3PO4　shows　excellent　photocatalytic　properties.　Based　on　the　Ostwald＇s　ripening　rule,　a　possible　formation　mechanism　of　cubic　Ag3PO4　was　proposed.　[GRAPHICS]　HIGHLIGHTS　Controlling　the　microstructure　of　Ag3PO4　through　pH-control　of　the　silver　ammonia　solution.　When　the　pH　of　the　silver　ammonia　solution　is　9,　the　preferential　crystal　growth　of　the　Ag3PO4　oriented　along　the　(1　1　0)　crystal　surface.　Based　on　the　Ostwald＇s　ripening　rule,　a　possible　formation　mechanism　of　cubic　Ag3PO4　was　proposed.