Abstract: We developed the sequence straitigraphy analyses for Pinghu Formation in Pinghu Slope,in Xihu Sag. Pinghu Formation belongs to the second sequence, which consists of 5 secondary parasequences. The development of sequence in Pinghu Slope are controlled by early faulting.It is frequently periodic sea level changes that dominate the origination, development and ending of sequence, and also dominate the general features of paleobiological style, system trct and depositional facies.There are lowstand system tract, transgressive sysiem tract and highstand system tract in Pinghu Formation, in Pinghu Slope. The transgressive system tract comprise lagoon and tidal flat dark mudstone, which are the main sourcerock in the area. The highstand system tract comtprise tidal channel and deltaic sandstcne, which are in good porosity and permeability, become he main retervior in the area. Pinghu Slopc are promising petroliferous area due to the favorecablc match of sourcerock, reservior and caprock, which are the result of the petrographic characters of different system tract.