Abstract: To analyze the hydrocarbon accumulation law of Zhuyi oil and gas zone in Pearl River Mouth Basin, this paper establishes a halfgraben hydrocarbon accumulation model on the basis of the halfgraben accumulation system in Zhuyi Depression, focusing on structural evolution and accumulation element combination. Based on analysis of the accumulation elements, such as source rock, hydrocarbon migration conditions and reservoir-cap assemblages in the different structural zones of half grabens, it is assumed that the hydrocarbon accumulation pattern of the half-graben ambulation system in the research area can be divided into four types – hydrocarbon accumulation assemblage in gentle slope zone, steep slope zone, sag zone and uplift zone. The main direction of hydrocarbon migration and hydrocarbon distribution patterns are determined by geological structure of rift lake basin, formation occurrence and fluid potential. From the angle of hydrocarbon resources distribution, the half grabens in the research area can be divided into three types of structure, such as gentle slope predominant half graben, steep slope predominant half graben and nearly balanced half graben. These three half grabens have apparently different distribution patterns of hydrocarbon accumulations.