In view of low permeability of the reservoir and high freezing point of the crude oil, the authors conducted a comprehensive research on reservoir damage, which included petrologic-mineralogical characteristics, pore structure, fluid roperties, sensitivity and water-drive features by using experimental analysis and xploitation test. On such a basis, it is held that the main factors responsible for reservoir damage are as follows: separation of paraffin wax in the crude oil resulted in the falling of the stratigraphic permeability near the bottom of the oil well; the reservoir near to the water-injection well was damaged by bad water_injection quality; particle migration caused deep stratigraphic damage, bacterial plug and stratigraphic sensitivity damage and so on. Based on experimental data analysis, the authors have reached some conclusions and also put forward a few suggestions and schemes for improvement.