Nitration of toluene was carried out with nitric acid(67%) in the presence of SO₃H-functional ionic liquids［SO₃H(CH₂)₄mim］X (X^-=pTSO-, CF₃COO^-, BF₄^-) to develop a green nitration process. Results show that ［SO₃H(CH₂)₄mim］CF₃COO has the best catalytic activity. The conversion of toluene can be up to 65.1%, the yield of mono-nitrotoluenes can be 40.7% and the ratio of ortho/para can be 1.24, when the mole ratio of toluene to nitric acid is 1：1, the absorption of ionic liquid is five percent of the substrate by molar, the reaction temperature is 80 ℃ and the reaction time is 22 hours.