Abstract: Several kinds of steel specimens with V-shaped engraved groove, at first were heated and kept warm at the austenitizing temperature for a period of time and then quenched in oil or water, thus the quenching martensite structure was obtained. Then the specimens were tempered and cooled in the air. When the specimen temperature was 300~350 ℃ (blue brittle temperature), the specimens were fractured promptly and then cooled in the air or with some insulation measurement, finally the well bluing fracture surfaces were obtained. According to the repeating testing verification, the results show that the even and distinct mazarine color appeared in the fracture surface obtained by this method, and the inclusions could be shown clearly without the negative factors to influence the inclusion evaluation.