Abstract: Fuzzy rough set model is a generalization of classical rough set model. However, it has its own defects and shortcomings. An improved fuzzy rough set model is established on the fuzzy rough set model. One domain is expanded into two domains, and the membership function of fuzzy rough set is redefined. Therefore, the new model's rough approximation accuracy and application range are effectively improved. This new model is proved to be effective and practical by theory and case analysis.

Key words: rough set, fuzzy set, fuzzy relation, fuzzy rough set model