Abstract: The reservoir heterogeneity of the Chang-6 pay sets of the Yanchang Foramtion in the Pingbei Oil Field is examined on the basis of the data of cores, well logging interpretation, experimental analysis and exploitation regimes. Four types of intrastratal heterogeneity are summaried:normal rhythms, reversed rhythms;composite rhythms and alternating rhythms. The widespread occurrence of interbeds results in the increase of the intrastratal heterogeneity.