Based on drilling, seismic datasets, etc, relationships between tectonic movement, palaeogeomorphology and sedimentary systems have been studied in the Rovuma, the Tanzania, and the Lamu basins, which were helpful for oil and gas exploration in the study area. The palaeogeomorphology, depositional center distribution, sedimentary environment, and sedimentary system can be controlled by tectonic movement. The results show ① plate tectonics event affected large scale palaeogeomorphology pattern and environment change. Because the India- Seychelles Plates and African Plate, the Indian Ocean extension, seawater southward invasion, the sedimentary environment changed from land to marine facies. The East Africa showed high west- low east topographic features for the Afar mantle plume and strata lift. ② The Mid- oceanic ridge arch and expansion, fault movement affected uplifts and depressions, sedimentary system distribution. The west depression belt, middle slope belt, and east abyssal plain belt were divided in the study area. Davie ridge consisting of East Davie and West Davie faults developed in east of the study area. There were four large- scale “fluvial- delta- marine fan systems” that developed from west to east in the Oligocene. Delta formed in the west depression belt, submarine fan developed in the middle slope belt, and deep- water deposits in the east abyssal plain belt, which are usually distributed in the west of Davie ridge. ③ Distribution and volume of sedimentary system were influenced by secondary faults, which mostly formed in the sags of west depression and middle slope belts. The sedimentary system shows northward deflection in the north of the Rovuma basin and south Tanzania basin, and southward deflection in the Lamu basin for sags and secondary faults.