A substrate and a photoelectric display device comprising the substrate are provided. The substrate comprises a display region (11) and seal material disposed in a periphery thereof. The substrate further comprises a trapping buffer region (13) which is disposed between the display region (11) and the seal material and receives photoelectric display media. By providing the trapping buffer region, impact on the seal material by the excessive photoelectric display media can be mitigated or eliminated when the photoelectric display device is subjected to an external force or is flexed. The life time of the seal material is prolonged. A leakage of the photoelectric display media is avoided.