Abstract: Marib-Shabwah Basin is a passive rift basin. It was resulted from the extensional tectonics of shear stress field. It is different from active rift basins formed by the uplift of mantle convection. The Mesozoic Era of the basin underwent two phases of rift, i.e., firstly strong and then weak. There are two sets of source rocks. Lam-Meem Formation generated in the first rift phase is the major source bed in the basin. Six hydrocarbon accumulation assemblages developed in the basin. The assemblage of Lam sandstone and Alif sandstone and the assemblage of Alif sandstone and Sabatayn regional cap rock formed the chief oil-bearing beds. The main traps include titled antithetic normal faults, drape traps, and salt structures. Research shows that Marib-Shabwah Basin has favorable hydrocarbon accumulation conditions and broad prospect for exploration

Key words: passive rift basin, geological mode, hydrocarbon accumulation mode, Marib-Shabwah Basin, Yemen