Abstract: A fracture dynamics analysis is given to an accident on a gudgeon link of the miter gate of a dam. The study gives a qualitative and quantitative dynamic fracture analysis, and a three-dimensional finite element program is developed to compute the dynamic stress intensity factor for a semi-elliptic surface crack in an elastic solid of finite size under impact loading. The results will be helpful to reveal the causes of the accident and to provide suggestions of precaution to avoid similar accidents.