The invention provides an X-ray detector applied to impurity detection. The detector comprises a conveyor line, double light source X-ray scanning equipment and information processing equipment, wherein the conveyor line is used for conveying detected articles; the double light source X-ray scanning equipment is used for generating two X rays for scanning the detected articles; the two X rays form a ray included angle; and the information processing equipment is connected with the double light source X-ray scanning equipment and is used for processing the information obtained after scanning of the double light source X-ray scanning equipment to form images. The X-ray detector based on double light sources can generate X-ray double light sources so as to project the detected articles in two directions to form two complementary X-ray detecting images, thus solving the intrinsic blind zone problem of the single light source detectors and improving the impurity detection accuracy rate.