Santos Basin has experienced three evolution stages: Early Cretaceous craton depression basin, early and middle Early Cretaceous rift basin and late Early Cretaceous Albian - Holocene continental margin basin. Oil resources are mainly enriched in the source-reservoir-cap assemblage of rift basin. The current division scheme of basin tectonic units can not accurately reflect the tectonic framework of rift period. According to the latest basic data of gravity and magnetism, seism, drilling and ocean drilling, a new scheme for the division of subsalt tectonic units in Santos basin is put forward: (1) Taking the main faults and sedimentary characteristics in the late fault depression period as the basis for the division of primary tectonic units, the boundary between uplift and depression is determined according to the faults distribution and the isoline of sedimentary thickness of 600 m in the late fault depression period. (2) Taking the secondary faults and sedimentary characteristics in the late fault depression stage as the basis for dividing the secondary tectonic units, the boundaries of bulges and sags are determined according to the distribution of synsedimentary tension faults, secondary strike slip faults and their regulating faults, combined with the 1000 m isoline of sedimentary thickness in the late fault depression stage and early depression stage. (3) The basin is divided into five primary structural units of "two uplifts and three depressions", including western depression, Aram-U uplift, central depression, Lula-Sugar uplift and eastern depression, and further divided into 38 secondary structural units. The tectonic units division based on the evolution characteristics of rift basins are of great significance for future oil and gas exploration and resource evaluation.