Kutai Basin, the biggest and the deepest Tertiary petroliferous basin in Indonesia, has undergone development stages of basin faulting, depression and reversion and is filled with 14km thick Tertiary sediments. Four sets of source rocks develop in the basin, among which the middle Miocene littoral deltaic plain coal and delta front carbargillite and the upper Miocene deep-sea carbon-rich clastic turbidite are the effective source rocks. Hydrocarbon are enriched in the middle and upper Miocene and Pliocene rocks in longitudinal and within the anticlinal structures in plane. It is suggested that the petroleum potential areas are the upper Miocene deep-sea slope fan sandstone and basin-floor fan sandstone in Lower Kutai Basin, the Eocene basin-marginal onlap pinch-out sand bodies in Upper Kutai Basin, Oligocene-lower Miocene rocks in Samarinda composite anticline belt and the Eocene-Miocene deep platform organic reefs.