Abstract: Abstract：In the Longdong area, Changqing oilfield, Ordos, casing corrosion and damage influence oil production seriously. The main cause is thought to be electrochemical and biochemical reactions between casing and formation water of Na2SO4 type in the Cretaceous Luohe Formation. The desert-facies sandstone of the Luohe Formation distributed uniformly in the whole basin is characterized by high permeability and homogeneity, so it can provide good conduits and spaces for the recharge, runoff and discharge of groundwater and the resulting strong leakage field accelerates casing corrosion and damage. Analysis confirms that only relying on raising the quality of casing and cementing is not enough to prevent casing corrosion and damage in the study area, and only by using new materials and technologies can we solve this problem.