Abstract: The elect ospinning technique was used to produce multi-walled nanotubes (MWNTs) and polyurethane (PU) compound ultrafine fibers. Thermal stability and dynamic mechanical properties of MWNTs/PU non-wovens were examined by the thermogravimetric analysis and dynamic mechanical analysis. The relationship between the direct current electrical conductivity and the mass fraction of the MWNTs was tested. The dynamic electrical conductivity in the range from 40 Hz to 110 MHz was measured by a dielectric spectroscopy using an Agilent 4294A impedance analyzer. The results show that the thermal stability is improved significantly with increasing the content 10 of MWNTs in the compound ultrafine fibers. The electrical conductivity of the membranes is improved 10 times compared with that of the pure PU when the mass fraction of MWNTs is 40 %.