Abstract: With applied systematic research ideas and modern petroleum geology theory, the main controlling factors for hydrocarbon accumulation in Bi Dian area of Biyang depression have been analyzed. The analysis results show Bi Dian area is of superior reservoir forming conditions. With good spacial configuration, various reservoir forming factors are close to the source center. The percentage of sandstone thickness is between 20%～40%. With staggered generating-reservoir-capping combination, the trap condition is found to be good. The discovered reservoirs in the area mainly belong to fault and lithology reservoirs, and the hydrocarbon accumulation and distribution are controlled by different factors.