Tannic acid (TA) was encapsulated on the surface of MOF-808 via a blending method to synthesize TA@MOF-808 composite nanomaterials. These nanomaterials were then incorporated into a polyetherimide (PEI) ultrafiltration membrane using the phase inversion technique. The TA@MOF-808 doped PEI ultrafiltration membrane was characterized by FTIR, XPS, SEM, AFM and contact angle measurements (CA)to assess functional groups, chemical structure, surface morphology, cross-sectional structure, surface roughness, and hydrophilicity. The results demonstrated that when the mass fraction of TA@MOF-808 was 0.04%, the ultrafiltration membrane exhibited superior performance, achieving a pure water flux of approximately 926.1 L·m-2·h-1 under an operating pressure of 0.1 MPa and a rejection rate of 93.9% for a 0.1 g/L bovine serum albumin (BSA) solution. In a 14-day long-term stability test conducted in a dilute sulfuric acid solution at pH 3, the pure water flux remained stable between 840-845 L·m-2·h-1, with a rejection rate of 97.5% and a flux recovery rate exceeding 93%, indicating excellent separation performance and structural stability.