The invention discloses a tire X-ray image detection and identification method and system. The detection and identification method comprises an offline training step and an online detection step. The offline training step comprises: (11), establishing a training sample; (12), performing defect detection on an image in the training sample, and computing defect information of the training sample; (13), performing quantization coding on the defect information of the training sample to obtain a training sample feature vector; and (14), training the training sample feature vector and a grade judging result into a grade judging model. The online detection step comprises: (21), collecting a to-be-detected tire X-ray image in real time; (22), performing detect detection on the to-be-detected tire X-ray image, and computing all to-be-detected tire defect information; (23), performing quantization coding on all the to-be-detected tire defect information; and (24), computing the to-be-detected tire feature vector and the grade judging model. According to the detection and identification method, artificial subjective factors are avoided, the judgment is more objective and unified, and the judgment efficiency and accuracy are both improved.