As　a　solution　to　complicated　system＇s　information　processing,　the　basic　idea　and　concept　of　rough　set　theory　are　described.　Some　current　studies　on　rough　set　theory　are　discussed,　which　are　focused　on　model　extensions,　reduction　algorithms,　and　applications　of　rough　set　theory　in　areas　like　machine　learning,　decision　analysis,　knowledge　discovery,　etc.　Further,　research　directions　about　rough　logic　control　and　rough　information　processing　are　put　forwards.