Many new ideas and concepts were proposed as a consequence of development in the abnormal fluid pressure studies, which have been promoting the advance of modern petroleum geology. On the problem of the relationships between abnormal pressure and hydrocarbon generation, majorities agreed with overpressure retardation of organic matter maturation and petroleum generation. The retardation is also favorable for the preservation of hydrocarbon. Under the condition of overpressured environments, hydrocarbon generation, expulsion, migration and formation of pools are always charactered by episodic pattern. Pressure driving force is a significant dynamic condition for fluid flow and hydrocarbon migration. In the overpressure environments, the dynamic migration routes that include hydraulic fractures, faults and fluid diapir structures may occur as consequence of hydrocarbon generation and overpressure development. The coincidence of excess porosity associated with overpressure is very commom. Most hydrocarbons production occurred in the transition zone between hydropressured and overpressured sediments. This knowledge has been provided a new approach to exploration in most sedimentary basins.  Unconventional hydrocarbon accumulation associated with abnormal pressure system, such as anomalously pressured tight gas sand or sweet-spots, hydraulic fracture-fractured shale reservoirs, and pools with petroleum overlain by water can be found in abnormally pressured sedimentary basins.