The pore structure inside the exfoliated graphite makes it have excellent adsorption performance, especially for the adsorption of oil molecules. Oily wastewater from simulated oilfield plant was prepared with diesel oil and oil extracted from oily sludge. The effects of mass ratio of oil to expanded graphite, adsorption time and pH on oil adsorption by expanded graphite were investigated. The optimum conditions for the adsorption of diesel oil by exfoliated graphite are as follows: the mass ratio of oil to graphite is 50∶7,the stirring time is 10 minutes, without adjusting pH.The optimum conditions for heavy oil adsorption are as follows: the mass ratio of oil to graphite is 50∶8, the stirring time is 10 minutes, without adjusting pH; and the adsorption of expanded graphite to oil conforms to the distribution adsorption law.