<p>This study utilizes cellulose acetate as the base material and employs Electrospinning as the fabrication process. By adding catechol and copper oxide, an antibacterial/antiviral nanofiber membrane (AANM) is formed. The AANM demonstrated a viral inactivation rate of over 95% against the H3N2 virus, as confirmed by the ISO 21702:2019 test method. Additionally, the AANM's antibacterial rate reached over 95%, as verified by the ISO 22196:2011 test method. The formulation of AANM was optimized by incorporating Hydroxypropyl Cellulose (HPC), which induced limited swelling of the nanofibers upon water absorption. This swelling effect subsequently reduced the breathability of the membrane, which was restored once the water evaporated. This feature endowed the AANM with dry–wet response morphological changes. Furthermore, the inclusion of shikonin, purified from gromwell, endowed the AANM with the capability for pH-responsive color change. The AANM based on cellulose acetate was prepared using a one-step method, providing not only antiviral and antibacterial effects but also dry–wet morphological responsiveness and pH-responsive color change. Using cellulose as the substrate, except for copper oxide which is an inorganic material, the functional additives are all extracted from plants, proposing another approach for the application of green functional materials.</p>