Abstract: The deepwater fan systems contain abundant petroleum and it becomes hot point field in petroleum explorations. Based on the sequence stratigraphy theory, a great variety of the sequence interfaces are identified, furthermore, great deals of deepwater fans are discovered. They are composed of basin floor fans, slope fans, lowstand wedges and downcut channels existing on the Baiyun Sag of the Pearl River Mouth Basin. The basin floor fans and the slope fans developed during several periods overlap each other in vertical, distribute lobately and horizontally, and connecte with downcut channels. On the basis of investigation, the main accumulation controlling factors of the Baiyun Deepwater Fan include: (1) The conducting frameworks, which are composed of faults, continue distribution sandstones, unconformable surface and diapiric zone, connecte the source rock and the deepwater fans and are the key factors of petroleum accumulation; (2) The drive power of oil and gas migration. Based on the basin modeling, there are three circles of strata pressure during the basin evolution. The accumulation and release of overpressure are important for the hydrocarbon expelling from source rock to deep water fans.

Key words: Pearl River Mouth Basin, sequence stratigraphy, Baiyun deepwater fan, accumulation conditions, main accumulation factors