Poly(acrylic acid)-Poly(ethylene oxide)/ Na-montmorillonite (PAA-PEO/Na-MMT) nanocomposite nanofibers with various weight ratios of clay have been fabricated by the electrospinning technique in aqueous solution. The influences of the MMT on the structure, morphology and thermal properties of PAA-PEO nanocomposite fibers, respectively, were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analyses (TGA) and differential scanning colorimetry (DSC). From XRD curves it was found, that there was no observable diffraction peak of clay layers, indicating that the silicate clay layers were well dispersed and exfoliated within the PAA-PEO nanofibers. However, the TEM images indicated that some of the multilayer stacks of nanoclays could be found within the nanofibers and were aligned along the axis of the nanofibers. PAA-PEO (1:1)/Na-MMT nanofibers were obtained with a diameter range of 150 to 300 nm. The SEM images showed that the fibers diameter was slightly affected by the amount of added Na-MMT. The DSC analyses suggested that increase in the melting point (Tm) of PAA-PEO/MMT nanofibers could be a result of the clay exfoliated platelets aligned along the axis of electrospun nanofibers.