1. School of Earth Sciences and Engineering, Xi'an Shiyou University, Xi'an 710065, China;
2. Shaanxi Key Laboratory of Petroleum Accumulation Geology(Xi'an Shiyou University), Xi'an 710065, China;
3. Langfang Branch of Research Institute of Petroleum Exploration and Development, PetroChina, Langfang 065007, Hebei, China;
4. The Tenth Oil Plant of Changqing Oilfield Company, PetroChina, Qingcheng 745100, Gansu, China

The formation and evolution of pre-Jurassic palaeogeomorphology in Ordos Basin was restored using the river terraces, valley shape and residual thickness in combination with seismic and drilling data. The results showed that Ordos Basin experienced two different large-scale tectonic events associated with uplift and erosion in Late Triassic, of which the first one was equilibrium uplift, with strong erosion, while the second one was broad and gentle V-type disequilibrium uplift，with relatively weak erosion. The formation of pre-Jurassic palaeogeomorphology was the erosion response to the Late Indosinian tectonic movement，which can be divided into two sub-episodes. With the ending of uplift erosion，valleys were filled with sediments, starting with the confined valley fill of Fuxian Formation, followed by the semi-confined valley fill of Yan10 section of Yan'an Formation.