Abstract: Jn order to increase predication level for hydrocarbon exploration in Tarim Basin, it is very important to evaluate the hydrocarbon bearing formations. From the analysis of avai - lible materials, it is undoubted that some groups of the Carboniferous, Permain, Triassic and Jurassic System could generate hydrocarbon. But the convincing judgement on the potentiality of the marine carbonate rock should be obtained a^fter further study. T hernia I- alteration index is a belter way which was suggested that the recovering evolution history of kerogen.
In most areas, it is neccessary to consider the possibility of mixture accumulation of poJysource hydrocarbon, then we could avoid prefering some bed of interesi to else drilled reservoirs during drillhole exploration.
The study of paleosttess fields is helpful to the analysis of formation mechanism and distribution regularity of traps and to the correct interpretation of other structure appearances; which adds to surface chemical exploration would be good to choosing the traps provided for drill hole exploration.