We have developed a novel extraction procedure based on PS nanofibers which were fabricated by electrospinning.By using the PS nanofibers, trace level of microcystin-RR and microcystin-LR were successfully extracted in environmental water samples.The microcystins were then detected by a high performance liquid chromatography (HPLC) with a photo diode alley detector (DAD) system.Parameters of influencing the extraction efficiency, such as amount of nanofibers, eluted solvent and volume, pH, and breakthrough volume of water samples were determined.Under the optimized conditions, a linear response for microcystin-RR and microcystin-LR over the range of 0.25-4 μg L1 was achieved with a r2 value of 0.998 and 0.997, respectively.The precision of the method was examined with relative standard deviations corresponding to 0.25, 1, or 4 μg L-1, and results were found to be less than 6% for both of microcystin-RR and microcystin-LR.Extraction recovery (absolute recovery) of microcystin-RR and microcystin-LR was found to be almost 100% at the above-mentioned three concentrations.For the concentrations between 0.05 and 0.25 μg L-1, the microcystins could also be detected by SPE joined with nitrogen gas.The proposed method was subsequently applied to studying water samples from lake and tap.All the results showed that PS nanofibers, as a adsorbent material has great potential for the enrichment of microcystins in the water samples with satisfactory recovery and repeatability.Due to its simplicity, selectivity and sensitivity, the method may be applied to quantitatively analyse the concentrations of other compounds in the environment.