Abstract: Two new technologies for clean steel detection were introduced: billet mirror processing and billet whole end surface detection. By the recently developed processing equipment—‘Heavy-type CNC Machine Tool Integrated with Ultra Precision Mirror Milling’, the roughness Ra on the whole end surface of steel billet may be less than 0.02 μm, and it is just as bright as a mirror. So the non-metallic inclusions could be detected on the billet end surface. And by the recently developed equipment—‘Large-type Comprehensive Metal Defect Detector’, the defects on the whole end surface of the billet may be automatically photo taken, counted, measured, calculated and analyzed. Supported by these two technologies, the clean steel detection could be finished on the billet and realized true macro cleanliness detection. This method has a great advantage and development prospect compared to conventional cleanliness detection method.