Abstract: It is attempted by this paper to systematically review the existing dynamic initiation criteria. Some well -known dynamic initiation criteria are:(1) Dynamic stress intensity factor criterion; (2) Dynamic J-integral criterion;(3) Least action criterion; and (4) Minimum time criterion. Some recent important experiments and some important conclusions obtained from experimentsare briefly introduced. It is generally agreed by the experiments that the dy namic fracture toughness of materials under small-scale yi...