Based on the fundamental principle of sequence stratigraphy

the storm wave base or offlap break of initial highstand delta system could be regarded as the reference for the"shelf break"in passive margin. Accoring to well log and seismic sections of sequence boundaries in cores

seven supersequences and 47 sequences are identified

and high resolution sequence stratigraphic framework is built in Cretaceous of Songliao Basin.The periods for the supersequences and sequences are about 11.29 Ma and 1.28 Ma respectively. To compare the curves of rise and fall of both the base level and sea level in Songliao Basin

their secondary cyclic variation tendencies are the same

but the frequency of third cyclic variation of the former is higher.This is caused mainly by the factors of local tectonics and complicated climate.