For the brittle fracture phenomenon of a certain type of Cr12Mo1V1 steel electric connection crimping mold after 200 times of service, the macro fracture morphology, material composition, mechanical properties and microstructure of Cr12Mo1V1 steel electric connection crimping mold were analyzed and detected by 5M1E failure analysis method, combining with the characteristics of cold working die steel Cr12Mo1V1 and using scanning electron microscopy, direct reading spectrometer, Rockwell hardness tester, metallographic microscope and other means, and the crimping process of the electric connection crimping mold was simulated by software Deform. The results show that the substandard material composition, low strength, uneven internal eutectic carbides and excessive carbide size of the electric connection crimping mold are the fundamental reasons for the short service life and brittle fracture of the mold. In addition, the unreasonable distribution of crack stop grooves and circular hole positions of the mold lead to stress concentration during the extrusion process, which is the main reason for brittle fracture failure of the mold. Finally, the life extension measures of electric connection crimping mold are put forward from the aspects of mold raw materials, heat treatment, forging process and mold structure design.