Yttrium　iron　garnet　(YIG)　crystals　are　the　primary　candidate　for　non-reciprocal　device.　With　the　miniaturization　and　integration　of　optical　communication　devices,　the　modified　YIG　crystals　with　excellent　comprehensive　performances　are　highly　desired.　To　explore　the　possible　mechanism　of　rare　earth　ions　doping　on　Faraday　effect,　holmium　oxide-doped　YIG　(Ho0.6Y2.4Fe5O12,　abbreviated　as　HYIG)　crystal　was　grown　by　molten　salt　method.　Its　structure,　optical　transparency,　magnetic,　magneto-optical　properties　and　oxygen　atmosphere　annealing　processes　were　first　investigated　systematically.　The　HYIG　crystal　wafers　annealed　at　800　degrees　C　for　2　h　can　achieve　the　large　Faraday　rotation　angle　(186　deg/cm　at　1310　nm;　148　deg/cm　at　1550　nm)　and　good　optical　transparency　(73.64　%　at　1310　nm;　74.83　%　at　1550　nm),　which　is　increased　by　approximately　10　%　compared　to　the　unannealed　sample.　This　result　may　provide　a　new　insight　into　the　investigation　of　rare　earth　doped　YIG　crystals　and　their　atmosphere　annealing　processes.