The demulsification performance of 3 fluorinated multi-block copolymers with dumbbell-shaped structure (FMCDSs) containing different hydrophilic polyethylene glycol (PEG) segment in diesel/water emulsion were investigated, and compared with the demulsification performance of polyether demulsifiers and dumbbell-shaped polyglycerol-PEG polymers. The results show: FMCDSs have better demulsification performance than hydrocarbon polymers; the chain length of PEG has a significant effect on the demulsification performance, and the FMCDSs with PEG-4000 as hydrophilic segments separated 95% oil from the emulsion within 30 min at a dosage of 300 mg/L(30℃). In addition, based on the results of interfacial tension and interfacial dilation rheology measurements, it can be found that FMCDSs can effectively adsorbed to the diesel-water interface, and the fluorined groups are the major factor in producing good demulsification properties.