Abstract: In order to effectively deal with imprecise linguistic terms in information tables and to improve the ability of dealing with initial fuzzy data, fuzzy indiscernibility relation is proposed. Some basic concepts of rough sets such as reduct and core of knowledge are generalized to the fuzzy environment. A heuristic algorithm is presented to simplify decision tables with fuzzy-valued attributes. A numerical example is given to prove that the proposed approach is suprior to the Pawlak’s typical approach and some other scholars’ works in the simplification of decision tables with fuzzy-valued attributes.