The preparation of inorganic/organic composite membranes has been demonstrated to bring together the advantages of ceramic and polymeric materials. However, the fabrication of inorganic/organic thin-film composite membranes in hollow fiber configuration has rarely been reported due to the complexity of existing methods. A facile and economic method, in-situ vapor induced hydrolyzation process, was proposed for preparation of Al2O3/Polyethersulfone (PES) thin-film composite hollow fiber ultrafiltration (UF) membranes. The amphiphilic copolymer of PEO-PPO-PEO was introduced to bridge the Al2O3 nanoparticles and PES substrate, resulting in a more stable deposition of Al2O3 on the substrate. The surface morphology and pore size of Al2O3/PES membranes could be precisely tuned by controlling the addition of aluminum precursors. The resultant membrane presented a MWCO of 22 kDa and a high pure water permeability (PWP) of 280 L m(-2) h(-1) bar(-1) due to the completely coated surface hydrophilic Al2O3 ceramic layer. In addition, the as-prepared thin film composite membrane exhibited a lower membrane contact angle than most other mixed matrix inorganic/organic composite membranes. Due to the higher surface hydrophilicity, the composite membranes showed improved antifouling properties to humic acid (HA). This in-situ vapor induced hydrolyzation process was demonstrated to be promising for fabricating thin-film inorganic/organic composite hollow fiber membranes with high performance in separation processes.