The Tianchi volcano in Changbai Mountains is one of the most famous volcanoes in the world, is an active volcano with the largest scale and potential danger in modern history. But they have not been confirmed by the historical records. By collecting, consulting, arranging, screening, textual researching and analyzing the huge amount of historical records, it is concluded that the Tianchi volcano in Changbai Mountains erupted extensively during A. D. 1014-1019, which has important significance on the study of the future eruption danger of the Tianchi volcano, Changbai Mountains.