The asymmetric wetting Janus fabric with double-woven structure was designed by using two systems of warp yarns and two types of the weft yarns with distinct wettability. The result shows that the fabric with double-woven structure possesses the asymmetric wettability with superhydrophobicity on one side while superhydrophilicity on the other side. This asymmetric wettability realizes a unidirectional permeation and oil/water separation effect. The efficiency of oil/water separation could be simply controlled by varying fabric densities; thus, suitable density should be regarded as an important factor in this system. In "water removal" mode, the separation efficiency and separation flux reached 99% and 2.5 L m−2 s−1, respectively. In "de-oiling" mode, the separation efficiency and separation flux reached 96% and 8 L m−2 s−1, respectively. According to this work, the as-prepared asymmetric wettability Janus fabric with double-woven structure is promisingly applied to oil/water separation and other related applications. [ABSTRACT FROM AUTHOR]