The separation of oil-in-water (O/W) emulsions can be achieved by using polyacrylonitrile (PAN) membranes. However, the general PAN membrane pores can be easily blocked by emulsion micelles and this severely decreases the membrane flux. In this work, high flux PAN membranes are prepared by doping with cross-linked fluorinated poly (N,N-dimethylacrylamide)-b-poly (4-vinylbenzylpentafluorophenyl ether-co-4-tert-butoxystyrene-co- 4-hydroxystyrene) (PDMA-b-P(VBFP-co-tBuOS-co-4HS)) block copolymer vesicles. By choosing the suitable degree of polymerization of each block, the synthesized cross-linked PDMA30-b-P(VBFP87-co-tBuOS44-co4HS19) vesicles have a relatively large size around 730 nm. Ascribed to the relatively large size of the vesicles and their different diffusion from the PAN chains, the vesicles doped membranes have 300 nm micro-sized pores on the surface and multi-layered structures containing the 500 nm micro-sized pores and 7 mu m macro-sized pores in the interior. It is demonstrated that the resultant membranes doping with block copolymer vesicles have excellent separation performance for a variety of O/W emulsions including whole milk.