There are many problems in the common baiting methods, such as bad cross-section quality, low efficiency and so on. In order to overcome these disadvantages, a new bar cutting technology based on high speed and restrained state is put forward in the paper. The cutting process and cutting mechanics were analyzed. The stressing intensity factor and fracture toughness were introduced to analyze the influence of loading velocity on the cutting surface quality. By means of the dislocation theory, the influence of loading velocity on the fracture process was researched. Numerical simulation and experiments were carried out, and the results were conformed well with the theoretical ones.