The traditional polyamide composite nanofiltration membrane has high selectivity. However, low water permeability is an important problem to be solved. Herein, the conventional polyamide composite nanofiltration (TFC) membrane was modified with nanoporous TiO2 (nTiO2) interlayer through vacuum-assisted strategy for enhanced water permeability. By tuning the nTiO2 nanoparticles loading, the nTiO2 modified TFC membrane with crumpled structure was fabricated. Besides, the thickness of polyamide layer was reduced due to the hydrophilicity and porosity of nTiO2. Because of the larger effective filtration area and thinner polyamide layer, the modified membrane had a permeability of 12.8 L m−2 h−1 bar−1 (increased by 20.8% than that of TFC membrane) and a rejection of 98.2% when filtering Na2SO4 aqueous solution. This work provided a solution for enhanced water permeability and extended the application of TiO2 in the modification of polyamide composite nanofiltration membrane.