Palaeozoic strata in the Chengdao area have abundant oil and gas. In order to reveal the mechanic origin of geological structures, Predict still unknown strctures and serve oil-gas prospecting, we made numerical simulations for the Indosinian, Yanshan and Himalayan tectonic stress fields of deformed Palaeozoic there by using the plane finite element method. In the Indosinian tectonic stress field there was a SN directional compression to dominate. The distribution of stress values corresponds for tWo level folds: early folds with NW-SE orientated axes and subsequent folds with nearly EW orientated axes. In the Yanshan tectonic stress field the maximum Principal stress converges southward and disperses northward -- consistent with the strike of Yanshan extensional faults. Small stress differences are a character of the Himalayan tectonic stress field. Such a stress environment is favourable for development of Small faults. Palaeozoic strata in the Chengdao area have abundant oil and gas. In order to reveal the mechanic origin of geological structures, Predict still unknown strctures and serve oil-gas prospecting, we made numerical simulations for the Indosinian, Yanshan and Himalayan tectonic stress fields of deformed Palaeozoic there by using the plane finite element method. In the Indosinian tectonic stress field there was a SN directional compression to dominate. The distribution of stress values ​​corresponds for tWo level folds: early folds with NW-SE orientated axes and subsequent folds with nearly EW In the Yanshan tectonic stress field the maximum Principal stress converges southward and disperses northward - consistent with the strike of Yanshan extensional faults. Small stress differences are a character of the Himalayan tectonic stress field. Such a stress environment is favourable for development of Small faults.