Abstract: Based on the principles of sequence stratigraphy,the paper described the basic characteristics of depositional system tract in the Lower Carboniferous.Field data showed that the system is a secondary cyclic sequence interbedded between 2 tectonic unconformities of the Early and Late Variscan periods.A transgressive system domain and a highstand system domain were developed within the sequence,with the sediments of lowstand system domain being absent. Favourable areas for oil/gas accumulation are barrier bar facies zones developed in the transgressive system domain and tidal channels developed in the highstand system domain.