Abstract: Based on the digital image intensifier performance allaround detection system,the detection method of image intensifier field defects is researched. After capturing a image with a defect, its property is known with digital imaging processing method. The field defect processing algorithm is based on the image gray feature extraction but not on the edge feature extraction. This algorithm is suitable to the objects which have quantitative and localized requirements. The experiment results show that this method can accurately detect field defects of the image intensifier.