Flexible and stretchable neural electrodes are promising tools for high-fidelity interfacing with soft and curvilinear brainsurface. Here, we describe a flexible and stretchable neural electrode array that consists of polyacrylonitrile (PAN) nanofibernetwork reinforced gold (Au) film electrodes. Under stretching, the interweaving PAN nanofibers effectively terminate theformation of propagating cracks in the Au films and thus enable the formation of a dynamically stable electrode-tissue interface. Moreover, the PAN nanofibers increase the surface roughness and active surface areas of the Au electrodes, leading toreduced electrochemical impedance and improved signal-to-noise ratio. As a result, PAN nanofiber network reinforced Auelectrode arrays can allow for reliable in vivo multichannel recording of epileptiform activities in rats.