Abstract: Block A in the southern Campos Basin in the deep water of Brazil has complicated pre-salt structures as a result of the Late Jurassic tectonic activity. Based on new 3D seismic and drilling data, the geological attributes, fault development and tectonic evolution of pre-salt in block A were reviewed. Four seismic reflection layers and three seismic sequences were identified in the pre-salt section. Block A also experienced three stages of tectonic evolution, including rifting, erosion and tilting as well as thermal subsidence. Additionally, NE and NNE normal faults are well developed in this region. Tectonic activity also resulted in a NW-SE transform fault in the region and this controlled the distribution of normal faults. Finally, the influence of tectonic activity on hydrocarbon distribution was discussed and it is expected to provide scientific basis for the pre-salt exploration activities in block A and Campos Basin.