Abstract: Based on the process oriented simulation principles of diagenesis in this paper,the effects of temperature,pressure,fluid and time four factors on diagenesis were considered comprehensively.By simulating the vitrinite reflectance of diagenetic parameters,paleogeotemperature,the smectite content in I/S mixed layers,the percentage content of authigenic quartz and the changing rules of sterane isomerization rate in time and space,the diagenetic history of a region was simulated and the spreading characteristics of diagenetic stages were predicted.And according to the controlling action of diagenesis to source rocks,reservoirs and caprocks as well as the matching relation of diagenetic history to tectonic developing history,the favorable exploration districts were determined.At last,the deep layers of Laoyemiao area in the Nanbao Depression of the Bohaiwan Basin were taken as examples to illustrate the application of this method.