Yong 3 Fault Block lies in the south of Yonganzhen oilfield in Dongying Depression and has very complex oil source relation. Based on the study of hydrocarbon accumulation condition of Es2 member sand body, this paper analyzed the oil and gas sources, reservoir properties, migration path and trap type, decided the main controlling factors of hydrocarbon accumulation and identified the hydrocarbon distribution and enrichment rule. It is considered that Yong 3 Fault Block has a good hydrocarbon accumulation conditions and the main controlling factors for reservoir forming are structure and sedimentary facies, so the reservoir distributions are affected by them. In plane, the oil-bearing zones are in middle and low steps. This study has great significance for the oil potential tapping of Yong 3 Fault Block.