The system does not require rotating or multi-camera system, only a single camera single shot can obtain 6 symmetrically distributed, can completely cover the object side image, suitable for M1.0 ~ M2.5 threaded hole inspection.The optical system has variable diaphragm, which can change the depth of field according to the demand; one-piece illumination design, which is convenient to lighten the inside of the threaded hole; double-mirror image design, with a larger working distance, which can meet the on-line rapid inspection.The software system adopts advanced industrial AI vision platform, users do not need to have professional AI algorithm capability, only need to upload defective pictures, the platform can automatically complete the deployment of AI models according to different inspection scenarios, providing inspection capability. It supports "low-resolution" and "low-contrast" image detection, and easily solves the difficulties in detecting defects such as "small scale, many types and few samples".