Here, a multifunctional poly (lactic acid)/copper-based metal–organic framework (PLA/CuMOF) degradable composite membrane featuring superior antibacterial and self-cleaning properties was fabricated via a simple electrospinning process for high- efficiency filtration/separation. Benefiting from the decrease of fiber diameter, the improved surface roughness and the surface charge of CuMOF, PLA/CuMOF fibrous membrane achieved excellent capture ability for ultra-fine particles and superb purification capability for real PM2.5 smoke. The differences of filtration capacity between PLA membrane and PLA/CuMOF membrane was further explored using analogue simulation with dynamic particle capture and airflow field distribution. Impressively, PLA/CuMOF fibrous membrane combines robust self-cleaning ability, effective antibacterial effect, and thermal management capability. Moreover, owing to the special selective wettability and chemical stability, PLA/CuMOF membrane possessed the stable oil–water separation performance under harsh environment (e.g., high acid, alkali, and salt). This degradable multifunctional filtration/separation fibrous membrane emerges a broad application prospect ranging from environmental governance, industrial security to personal protection.