This paper reports the design, fabrication, electrical and thermal characterization, as well as attachment and stability of a flexible photoelectric neural interface (PENI). Upon the wire-bonding technology, three micro LED (mu LED) chips are well-connected to the polyimide substrate as an array, with their luminous surfaces over against the holes. Meanwhile, a Parylene-C-based array with four microelectrodes (200 mu m in diameter) modified by sputtering iridium oxide film is fabricated to record micro electrocorticography (mu ECoG) signals. Then, the back-to-back assembly is utilized to allow blue light through the aligned holes on both arrays with almost no attenuation. As an optogenetics tool, the PENI can be attached on the cortical surface of a mouse expressing ChR2 to realize synchronized light modulating and neural signal recording.