Abstract: Generalized Ziarko' s variable precision rough set model and generalized rough fuzzy set model were introduced and the drawbacks of them were found. Based on support relative error ratio and error parameter β(0≤β＜0.5),the generalized variable precision rough fuzzy set model was proposed. The basic properties of approximation operators were investigated. hhc relation of between this model and generalized Pawlak's rough set model,generalized Ziarko's variable precision rough set model and generalized rough fuzzy set model was analysed in detail. Finally, the definitions and the approaches of approximation reduction were discussed, an example was given to illustrate the validity of the presented algorithms.

Key words: Variable precision rough set, Rough fuzzy set, Generalized variable precision rough fuzzy set, Approximation reduction