Abstract: The separation of aromatic hydrocarbons or olefins from paraffins is very important in chemical industry.The volatile organic solvents used are usually harmful to environment and human health.As green solvents，room temperature ionic liquids are potential substitutes for the separation of hydrocarbon products.Activity coefficients at infinite dilution of hydrocarbon solutes，such as alkanes，hexenes，alkylbenzenes and styrene，in 1-butyl-3-methyl imidazolium hexafluorophosphate (［BMIM］［PF₆］)，1-allyl-3-methylimidazolium tetrafluoroborate (［AMIM］［BF₄］)，1-isobutenyl-3-methylimidazolium tetrafluoroborate (［MPMIM］［BF₄］) and ［MPMIM］［BF₄］＋AgBF₄ were determined by gas-liquid chromatography.The measurements were carried out at different temperatures between 298.15 K and 318.15 K.The separation effects of these ionic liquids for olefin/paraffin, alkanes/benzene and hexene isomers were discussed.