Abstract: Preparation of thin section of oil saturated rock sections of different reservoirs,such as sandstone,conglomerate and carbonate rock,must adopt different technologies to maintain original structure of rock samples and original distribution of oil.The key is how to make rock samples concrete.Usually samples may be soaked and concreted in epoxy resin under the conditions of normal pressure and vacuum or normal temperature and normal pressure.For the incompact and oil saturated rock samples,it is necessary to concrete and fix them on the slide glass by glue 502 or epoxy resin and grind them flat at first,then the thin sections can be made.