Abstract: Based on equivalence relation, knowledge representation system (KRS) and knowledge reduction algorithms were established by rough set theory (RST). Tolerance relation is extension of equivalence relation. KRS, upper and lower approximation, knowledge dependency and discovery of association rules of tolerance system were defined and computed by granular matrix.

Key words: Granular computing (GrC) , Rough set theory (RS7)，Granular matrix (GrM) , Tolerance relation, Association rule