The electrospinning of sulfonated poly(phthalazinone ether sulfone ketone) (SPPESK) and its blend with polyether sulfone (PES) were investigated and the blend nanofibers were applied as a catalyst in esterification. Attempts to electrospin pure SPPESK resulted in electrospraying rather than electrospinning. However, a blend polymer solution of SPPESK and PES resulted in smooth electrospinning when SPPESK content was lower than 9 wt%. The geometrical properties such as fiber diameter and distribution, surface chemical properties such as inter-molecular interaction and crystalline, mechanical properties were investigated by SEM, FTIR, XRD, etc. The catalytic activities of SPPESK-PES nanofibers were measured by esterification of ethanol with acetic acid. A pseudo-homogeneous model was established to describe the kinetics of esterification with nanofiber as a catalyst. The results showed that the SPPESK-PES blend nanofiber had a high specific surface area (46.7-58.9 m(2)/g), good mechanical properties, good catalytic properties (ethanol conversion up to 80 % when reacted 8 h), and good forward rate constants (10.0x10(-3)-14.6x10(-3) L/(mol min)).