The　grey　world　algorithm　is　discussed　in　detail,　and　two　improved　grey　world　algorithms　are　proposed,　to　overcome　the　limit　that　the　algorithm　may　be　ineffective　in　the　case　of　few　colors　or　large　union　colors　image　which　are　based　on　standard　deviation　weighted　algorithm　and　based　on　image　entropy　constraint　algorithm　respectively.　The　algorithms　are　evaluated　in　two　aspects:　the　color　correction　results　are　compared　subjectively　(visually),　and　the　performance　is　evaluated　objectively　using　color　difference　data.　The　experimental　results　show　that　the　improved　algorithms　have　better　correction　effect　on　both　real　capture　images　and　downloaded　images.