The stratigraphic neutral surface of a folded bed means neither elongated nor shortened a non-strain plane, above which it is called upper neutral surface and below which it is called lower neutral surface. The places where the upper neutral surface of an anticline and the lower neutral surface of a syncline are in a status of tensile stress(T) are the favorable hydrocarbon-gathering areas，while the places where the lower neutral surface of an anticline and the upper neutral surface of asyncline are in compressional zone (C) are the hydrocarbon-discharged areas. If hydrocarbon is migrated from the compressional zone to the tensional area, it is defined as "C-T" accumulation model. In the Mesozoic-Paleozoic marine formations in southern China, anticlines are almost exposed to denudate and traps, i.e. the upper neutral surface of anticlines, are commonly destroyed but the lower neutral surface of buried synclines keeps intact yet and gets shoaling with denudating of overlying，which brings in getting easy for commercial oil prospecting. Therefore we can change our idea to prospect for the lower neutral surfaces of synclines，which may be able to become new petroleum prospecting targets in Mesozoic-Paleozoic marine formations in southern China in future.