The　light　conversion　film　Er:YbF3,　which　has　not　only　the　up-conversion　property　but　also　the　down-conversion　property,　was　successfully　prepared　on　Si　(100)　substrat.　The　effect　of　substrate　temperature　on　films　structural　and　optical　properties　was　further　studied.　The　results　showed　that　the　film　achieves　combination　of　up-conversion　and　down-conversion.　It　can　effectively　convert　ultraviolet　light　and　near　infrared　light　into　656　nm　which　is　the　best　response　range　to　amorphous　silicon.　With　increasing　temperature,　the　crystallinity　of　the　films　were　improved,　but　when　substrate　temperature　exceeds　500°C,　the　impurity　phases　are　found　in　the　films.　These　results　showed　that　optical　properties　of　films　with　500°C　were　optimal.　Moreover,　the　light　conversion　Er:YbF3　film　may　improve　photoelectric　conversion　efficiency　of　amorphous　silicon　solar　cell.