Chinese Cambro-Ordovician sequences, particularly from the Tarim, Ordos, Bohai Gulf and Sichuan Basins contain important petroleum reservoirs and are relatively well studied. Five types of structurally related reservoirs are modelled in these basins; most reservoirs are close stratigraphically to the unconformity between the pre or middle Ordovician and younger Late Palaeozoic, Mesozoic and Cainozoic sequences. The source rocks of these basins are either Cambro-Ordovician or younger overlying sequences and have complex generating histories. Of four basins, especially the Tarim Basin, carbonate petroleum reservoirs are deeply buried, normally between 5000-6000m below the surface, mostly producing gas rather than oil. Four trap types are recognised in the Early Palaeozoic sequences of the Chinese basins: 1) anticlinal structures; 2) palaeohigh structures with overmature or re-migrated gas; 3) palaeohighs or in non-structural strata; 4) palaeokarst (buried hill) traps often by well developed porosity and permeability.