Abstract: The degree of exploration of Haizhong Depression nowadays is low which is located in the southwest of Beibuwan Basin and petroleum accumulation conditions here needs to be understood and studied comprehensively. Based on the introduction of structure and formation characteristics, this paper emphasizes on the basic elements of petroleum system such as generating rocks, reservoirs, traps, and migration mediums. It is concluded that there are series of source rocks, reservoirs, kinds of traps and migration mediums developed in Haizhong Depression, which means it has pool forming conditions and cheerful prospect.