Previous studies showed that Expanded graphite(EG) prepared by wet processing used mixed acids. wet processing had a environmental problem about waste management. In this study, dry processing was utilized in preparation expanded graphite to supplied defects of wet processing. The SO3 intercalated graphite was prepared by drying process that leaded to the intercalation into the direct reaction of SO3 gas with flake graphite. reaction condition was controlled by various processing parameter for controlling of adsorbing properties of EG. expanded index increased with increasing heat treatment temperature and their maximum adsorption of heavy oil increased. the characteristics of the micro-structure and pores were investigated by the SEM and mercury porosimetry. The interlayer SO3 molecules were ejected by the rapid heating at 950 ℃ under an oxidizing atmosphere for about 1 minute, resulting in surprisingly high expansion in the direction of c-axis. The expansion ratios of the expended graphites were increased greatly 220 times to 400 times to the original graphite particle and the bulk density were a range of 0.004 to 0.01 g/cm3, depending on the reaction time. he oil sorption capacity (g) per g-EG was 58.8 for bunker-c and 34.7 of diesell oil and the adsorption completed within a several minutes.