Porous electrospun nanofibers, as new materials for solid-phase extraction, were synthesized by electrospinning and coupled with ultra high performance liquid chromatography and mass spectrometry to determine sulfonamide residues in environmental water. Aligned porous polystyrene electrospun nanofibers were fabricated under the mechanism of phase separation. The high-specific surface of these nanofibers (70m(2)/g) could improve recoveries of the target sulfonamides 4-10 times compared with that of polystyrene nonporousmaterial (3.8 m(2)/g). Under the optimized conditions, 13 sulfonamide residues showed an excellent linear relationship in the range of 0.125-12.5 ng/mL with a linear correlation coefficient (r(2)) greater than 0.99, and the detection limits of sulfonamides were as low as 0.80-5.0 ng/L. Compared to the commercial C-18 and HLB columns, the homemade porous nanofibers columns had some merits including simple fabrication and extraction process, short process time and environmental friendliness. The optimized method was applied to eight water samples collected from different livestock farms (Xuzhou, China). The results showed that polystyrene porous nanofibers were promising to preconcentrate sulfonamides of different polarities in the waste water.