Abstract: Cangdong fault, 230 kilometer long, is a famous fault in east China. The middle section from Nanpi to Tanggu, 145 kilometer long is of petroleum geological significance. There are 110 seismic lines crossing through Cangdong fault. Texture of the reflection from fault plane shown in seismic profile can be divided into four type: (1) Spoon shaped, (2) Listric shaped, (3)Step shaped and (4)Scarp shaped. Their origin can be interpreted as follows: (1) Spoon fault was caused by either tensoshear stress or shear plane eroded by water. (2) Listric fault was formed from difference in dissolution caused by erotion of various Precenozoic rocks on upthrow block. Step fault was caused by slide of Precenzoic rockmass on uptrow block. Scarp fault was caused by upthrust of this basecment rock from uplift to depression. The stress pattern of Cangdong fault during Meso-Cenozoic Era shows a right-hand rotational feature. The Precenozoic paleogeologic map was constructed based on data from a limited mumber of exploration wells together with a large amount of seismic data. The map shows that Cangdong fault is situated on a paleozoic anticlinal ridge. The anticlinal core is situated between Xingji and Beitaoxian A half part of this anticline is situated on Cangxian uplift, with an other part inside the Cangdong depression. The axisl trends 22 degrees NNE approximatively and shows a low angle intersection with Cangdong fault. The width of Cangdong fault plane is in a range from 5 to 13 kilometers. An area of more than 1000 square kilometer is favorable for oil and gas exploration. Main trap types are as follow: (l)Basement rock buried hill on fault plane; (2) Rollorer fold on fault step, j (3).Nappe below fault plane; (4) Alluvial fan on fault scarp and (5) Remanant hill etc. Several decade of such traps have been discovered presently.