With　continuous　research　on　photocatalytic　water　splitting,　searching　for　efficient　catalyst　for　hydrogen　evolution　reaction　(HER)　becomes　popular　topic　in　addition　to　main　catalyst　research.　Transition　metal　phosphides　are　receiving　intense　attention　due　to　its　abundance　in　the　Earth＇s　crust　and　comparable　catalytic　properties　to　noble　metals.　In　this　review,　the　synthesis　approaches,　HER　reaction　mechanism,　photocatalytic　activity,　approaches　to　improve　the　activity　of　transition　metal　phosphides　were　reviewed　and　discussed.　It　was　showed　that　the　transition　metal　phosphides　have　great　potential　to　reduce　the　cost　of　photocatalyst　and　promising　application　on　water　splitting.　The　stability　problem　and　participation　of　poisonous　reactant　and　product　in　its　synthesis　reaction　limit　its　application　and　developing　in　a　certain　extent,　but　with　the　continuous　efforts　on　the　development　and　improvement　of　the　synthesis　methods,　transition　metal　phosphides　will　find　wide　application　in　water　splitting.　(C)　2017　Science　China　Press.　Published　by　Elsevier　B.V.　and　Science　China　Press.　All　rights　reserved.