Nanoporous preoxidated polyacrylonitrile fiber mat was prepared by electrospinning and thermal treatment for the immobilization of palladium catalyst. The fiber morphologies were characterized by scanning electron microscopy (SEM). Infrared spectra and X-ray powder diffraction characterizations (XRD) showed that thermal treatment of fiber mat could change the linear polyacrylonitrile structure into ladder structure. XRD was used to study the chemical nature of the palladium in the fiber mat. The catalytic activity and stability of the fiber supported palladium catalyst have been evaluated by the Mizoroki-Heck and Sonogashira cross-couplings. The larger structure of the fiber mat can greatly facilitate its separation and recycling. The excellent catalytic performance and easy recycling made this novel fiber mat supported palladium catalyst hold great potential for the green chemical processes.