This paper studies the forming factors of giant oil and gas fields in the coastal basins of West Africa, and summarizes the fields′ distribution rules in order to help the hydrocarbon exploration in the future. Based on the distribution of sedimentary basins and giant oil and gas fields in West Africa Coast, the factors of its forming is analyzed, the similarity and difference of two petroleum systems in Niger delta basin and Low Congo basin is summarized and than the giant fields distribution rules are identified. In the coastal basins of West Africa, the deposit of salt rocks has crucial effects to the oil and gas generation, immigration, and accumulation.