In this paper,the author studies the rough sets used matrix.First,the upper and lower approximation operators of Pawlak rough sets,fuzzy-rough sets,rough-fuzzy sets are redefined using the matrix representation;then the properties of these upper and lower approximation operators are discussed;at last,the definitions of the upper and lower approximation operators of Pawlak rough sets,fuzzy-rough sets,rough-fuzzy sets are unified through the compound operator of matrix.The matrix approach afford not only a simply computing method of the upper and lower ...