Abstract: The eastern branch of the East African Rift System is composed of several basins. It remains low in hydrocarbon exploration degree and only in the South Lokichar basin there are oil discoveries. The paper is to analyze the geological conditions for hydrocarbon accumulation in the South Lokichar basin with drilling, seismic and laboratory data. The study shows that the South Lokichar Basin has favorable conditions for oil and gas accumulation. Both of the Lower Auwerwer Formation and the Lokhone Shale Formation have oil accumulations being found and the former is the main exploration target. The western steep slope zone is the main hydrocarbon accumulation zone, in which both of the exploration targets have oil discoveries. Reservoir is the main factor affecting oil and gas accumulation and net pay thickness. The eastern gentle zone has little discovery until now, in which the main exploration target, the Lower Auwerwer Formation, has nothing discovered yet and poor lateral sealing is proposed as the main factor.