We demonstrated a dual-functionalization strategy of polymeric membrane with both "defensive" (adhesion resistance) and "offensive"(bacterial inactivation) efficacies via combining external-hydrophilic beta-cyclodextrins (beta-CDs) and bactericidal enrofloxacin (ENR) for combating biofouling. beta-CDs were immobilized onto polydopamine (PDA) pre-modified membrane surface, followed by host-guest assembly of ENR. Both static adhesion tests and dynamic fouling experiments implied that the CD-modified membranes showed significantly reduced adsorption and lower water flux decline against organic foulant. The enhanced "defensive" (fouling resistance) capacity of CD-modified membrane was mainly attributed to hydrophilicity improvement. Next, antimicrobial tests demonstrated that the integration of ENR in the functional layer could improve the "offensive" (biocidal) activity of modified membrane. Conspicuous reduction in biomass and ATP content further illustrated that the PVDF/CD-ENR membranes could effectively suppress biofilm formation during dynamic cross-flow biofouling tests. Finally, flow cytometry (FCM) assessment was first combined with heterotrophic plate counts (HPC) method in the present study, implying that the antimicrobial mechanism of the dual-functional membrane lies in inhibition of bacterial breed without disrupting the cell membrane.