Abstract: The determination of the dynamic fracture toughness K1d on wheel steel web is proposed in this paper. The testing results show that the dynamic fracture toughness do not present the same regulation with total impact energy Wt under the higher temperature. When the temperature decreases to -20 ℃, the K1d and Wt appear the synchronous trend. At this time, the brittle fracture is the main pattern of the fracture. Under this temperature, the total impact energy Wt can be used as the main technique parameter to identify the R7 wheel steel web dynamic fracture toughness good or not.