For a long time, alkali is the main modification reagent for ramie modification due to its good effect and low cost. However, the large consumption of alkali in the processing leads to a serious pollution to the environment. To develop a new eco-friendly modification method, a mixed green solvent composed of 95 wt% 1-butyl-3-methylimidazolium chloride ionic liquid and 5 wt% water was employed in the paper. The swelling ratio, surface composition and crystal index was studied in detail with video microscope, FTIR and XRD analysis. Results showed that the solvent system had a distinct swelling effect on ramie. The crystal index of ramie fiber decreased from 74.2 % to 54.5 % after the treatment. Otherwise, the modification also removed some gummy substances including 75 % content of pectin in ramie. These changes improved the wetability and dyeing properties of ramie. However, the treatment also did much harm to the tensile strength.