The Colorado basin in the Atlantic coast of eastern Argentina is a less explored passive continental margin basin with a number of exploration wells have been drilled with hydrocarbon displays . The basin has mainly experienced three evolution stages: pre rift period, synrift period and post rift period. The post rift period can be divided into thermal subsidence stage and passive continental margin stage. During the synrift period from Late Jurassic to early Cretaceous, the rift extension formed graben and half graben structures, creating a large amount of accommodation space, and the thickness of sedimentary strata in the central depression reached 15 km. According to drilling and seismic interpretation data, combined with structural and sedimentary facies analysis, it is considered that there are sufficient conditions for oil and gas generation, migration, accumulation and preservation in the basin. The most favorable play is the Colorado formation in the eastern part of the basin. The lower Cretaceous lacustrine shale is the source rock, and the shallow marine sandstone is the reservoir, which is mainly stratigraphic trap. The main risk of exploration lies in whether oil and gas can migrate from hydrocarbon generating depression to the reservoir at the edge of the basin for a long distance, and whether the top cap rock can prevent hydrocarbon from escaping.