This work was aimed to study the effect of different organic solvents; methanol, ethanol, ethyl acetate and methyl acetate on some properties of wild silk fibroin (Eri; Samia ricini). Morphology, secondary structures and thermal properties of the silk fibroin (SF) after treatment were investigated by using scanning electron microscope (SEM), attenuated total reflection infrared (ATR-IR) spectroscopy and thermogravimetric analyzer (TA), respectively. The results showed the surfaces of SF after treatment with those of organic solvents were slightly smooth compared to the control sample. The ATR-IR spectra indicated that methanol has most effectiveness on the transitional change of the SF structure. This was implied from the absorption peaks of the sample treated with methanol were shifted into lower wave number compared to other. With TG, DTG and heat flow results, the organic solvent can be divided into two groups; methanol/ethanol and methyl/ethyl-acetate. The results showed that maximum decomposition temperature and exo/endothermal of the SF treatment with methyl/ethyl-acetate were higher than that of methanol and ethanol treatment. This was suggested that the organic solvents might be affected on the SF properties with different mechanism or region of action.