A method of fabricating flexible neural microelectrodes based on non-photosensitive polyimide PI-5J was proposed, and a novel flexible neural stimulating microelectrode array was designed and fabricated by the traditional photolithography process for animal implantation. The degeneration and electrical characteristics of this fabricated microelectrode array were tested in vitro. Its biocompatibility was tested in vivo. The results show the array's good degeneration-resistance, good biocompatibility and good electrical characteristics, which are the bases for its next stage tests in vivo. The fabrication method of the flexible microelectrode array proposed in the paper will promote the basic research on neural science, and the treatment, the rehabilitation of neural diseases.