Abstract: On the basis of previous achievements,through the observation of a great deal of joints,faults and folds in field and under well and the classification of formation sequences of structures,it is studied in this paper the Mesozoic and Cenozoic tectonic stress fields and the relationship between tectonic stress fields and hydrocarbon accumulation in the Ordos Basin.The directions of the main tectonic stress fields in the basin were NW-SE,NNE-SSW and SN which controlled the first hydrocarbon migration and accumulation during the Indosinian movement.During the Yanshanian movement,it was NW-SE which controlled the second hydrocarbon migration and accumulation.During the Himalayan movement,it was NNE-SSW which controlled the final migration,adjustment and accumulation.