The efficient separation and recovery of oil from water-in-oil emulsion poses a great challenge because of the rapid development of the petrochemical industry throughout the world. In this study, a facile method to develop a ZIF-8 functionalized hierarchical micronanofiber membrane for high-efficiency oil/water separation was investigated. The electrospun PVDF/ZnO membrane was made, on which ZIF-8 crystal seeds were then created with the revitalizing step and expanded in the growth step, and finally functionalized hierarchical micronanofiber PVDF-g-ZIF-8 membrane was obtained. Results showed that oleophilic ZIF-8 crystals on the surface of PVDF membrane dramatically increased the wettability of oil and tuned PVDF membrane from olephobicity to oleophilicity. The hydrophobic/lipophilic PVDF-g-ZIF-8 membrane with a water contact angle up to 158 degrees and a toluene contact angle down to 0 degrees provides its separation efficiency for water-in-oil emulsion of 92.93% in an environmentally friendly and energy-saving manner. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46462.