Abstract: Substantial natural gas fields have been discovered recently on the East African coast. However, the exploration level is still low and the principles of gas accumulation remain unclear there. The Mozambique Basin in East Africa has shown great potential for gas accumulation. Study of structural and sedimentary geology, source rock, reservoir, seal conditions and petroleum system is required for evaluation of hydrocarbon potential and selection of favorable exploration targets in the region. There are various structural styles in the basin and the Karoo stratum is widely distributed. According to the data available so far, there are three sets of potential source rocks, and the Cretaceous marine mudstone provides the major gas sources. The confirmed reservoirs all occur in the Cretaceous, namely the Domo Formation and the Lower Grudja Formation sandstones. The main seals also occur in the Cretaceous. There are two petroleum systems, namely the Cretaceous Grudja/Domo and the Permian Coal Seams. The favorable exploration areas include the Zambezi Delta, the northern land, the Beira area, the Inhambane area and of the Palmeira and Limpopo grabens.