Abstract: The instrumented impact test was carried out by using the typical fracture material 34CrNiMo6 alloy steel, and the instrumented impact test method for evaluating the ductile-brittle transition temperature of fracture metal materials was summarized. The results were basically consistent with the ductile-brittle transition temperature obtained by the temperature-energy and temperature-side expansion value evaluation methods. The results show that the instrumented impact test method was more stable and reliable, and the instrumented impact test method could be used to evaluate the ductile-brittle transition temperature of mixed fracture materials that couldn’t be directly evaluated by visual observation.