In this paper, we introduced λ - upper Level set, strong λ - upper Level set, λ - lower Level set, strong λ - lower Level set, λ - upper weight Level set, strong λ - upper weight Level set, λ - lower weight Level set and strong λ- lower weight Level set in Pawlak approximation space. And discussed the constructive properties of rough fuzzy sets based on some kinds of level sets systematically. We devoted many efforts to study the represent theories and extended theories of rough fuzzy sets, and finally we gained the represent and extended theories based on four different level sets and detailed poof of the theories was given.