Cellulose nanofibers (CNFs) and cellulose diacetate (CDA) are mixed by solvent substitution method using dimethyl sulfoxide/trichloromethane as a new two-component solvent system. Cellular carbon fiber (CF)/Polylactic acid (PLA) composite supports are directly printed by fused deposition modeling (FDM) 3D printing technology on parallel conductive plates. CNFs/CDA composite nanofibrous composite membrane devices based on 3D printing technology are fabricated by directly depositing CNFs/CDA composite nanofibrous composite membranes on CF/PLA composite supports using electrospinning technology. The morphology and structure of the prepared CNFs/CDA composite nanofibrous composite membranes are characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). And the adsorption performance of the CNFs/CDA composite membrane devices on protein is determined. The results show that when the content of CNFs is 0.5%(in mass), the average diameter of the CNFs/CDA composite nanofibers is up to (381±116) nm, and the diameter distribution of nanofibers is more uniform, and the diameter of more than 80% nanofibers is in the range of 200—500 nm. In addition, the CNFs/CDA nanofibrous composite membrane devices based on 3D printing technology have good adsorption capacity for bovine serum albumin (BSA), with the maximum adsorption capacity of 433.89 mg/g.