Abstract: A peculiar seismic event occurred on Oct. 6,1597,which was widely reported in the historical documents of 7 provinces of eastern China. It has been inferred that the event was centralized in the Gulf of Bohai.It's notable features were:1.The area affected was very large,and everywhere was quite similarly shaken;2.No builing damage was reported,nor strongly felt shaking,but significant motion of both surface and underground water were widely recorded;3.Surface fissires appeared in some places;4.Volcanic eruptions which are thought to be probably related to the event,took place on the same day and the third day (Oct. 8) in the Changbai mountain area of China and Xianjindao of nothern Korea.Study of historical records leads to the impression that the ground shaking caused by the event had abundant long period components,and the event itself is likely to be a slow eathquake.