A detection and repair system includes an optical microscope, an image-retrieving device, an emission detector, a data controller, and a laser beam generator. When detecting the location of a defect, the system charges a detected region of an organic electroluminescent device with a negative bias or low forward bias before the device is lighted on. Then, the emission detector detects the locations of defects, which generate emission such as photons, thermal or IR emission, in an enlarged image. The laser beam generator generates a laser beam, which is used to isolate one of the defects. Furthermore, this invention also discloses a method for detecting and repairing an organic electroluminescent device.