A novel polylactic acid (PLLA) fiber membrane with nanoporous structures has been successfully developed via thermal-nonsolvent induced a phase separation technique by electrospinning a single solvent system of PLLA/dichloromethane. A water bath receiver was necessary for preparing the nanoporous fiber membranes in this paper. The results showed that the nanoporous fiber membranes could be obtained within a wide range of humidity. Compared with non-porous PLLA fiber membranes, the nanoporous fiber membranes displayed significantly improved specific surface area (improved about 20%) and rejection ratio (about 3 times) toward methylene blue. Besides, the PLLA nanoporous fiber membranes showed a water flux up to 4836.6 L m(-2) h(-1), increased by 25% than that of the non-porous fiber membranes. In addition, the oil adsorption capacity of the PLLA nanoporous fiber membranes could reach 26.8 g g(-1). The new developed PLLA nanoporous fiber membranes via thermal-nonsolvent induced phase separation technique would demonstrate an impressive prospect for oil adsorption and organic dye filtration. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.