Abstract: The hot ductility experiment of Q460C continuous casting billet was done on Gleeble-3500 thermal/mechanical simulater. The dependence of hot ductility on temperature was researched. The temperature domain of brittle zoon was found to be 650～950 ℃ by the dependence curve of reduction of area on temperature, the percentage reduction of area was 45%～37%, and then the fracture mechanism was analyzed. The results would provide theory data for production of Q460C continuous casting billet.