Abstract: The primary reason for cracking failure of the 16Co14Ni10Cr2MoE steel extractor was analyzed from force status of the extractor on working, fracture morphology, microstructure and surface hardness. Results indicate the 16Co14Ni10Cr2MoE steel had super high strength, but low toughness led to network cracks on the surface during the repeated high-speed impact. Some cracks propagated through surface compressive stress layer resulted from shot peening and then extended to the deep part. Higher temperature tempering was suggested to solve this problem because of toughness improving by little sacrifice of strength.