Abstract: In this study, influence of intermolecular interactions between Silk Fibroin (SF) and Poly (ε-Caprolactone) (PCL) in homogeneous blend form on SF conformation changes and thermal properties of the blends was investigated and discussed. The SF/PCL blends were prepared by solution blending and precipitating method, respectively. Dimethylsulfoxide and isopropanol were used as a solvent and a non-solvent, respectively. The blends were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermo Gravimetry (TG) and Scanning Electron Microscopy (SEM). Conformation transition of SF component from β-sheet to random coil forms can be induced by blending with PCL. Melting temperature and heat of melting of the PCL decreased as increasing the SF ratio. Thermal stability of the SF can be enhanced by blending with PCL. FTIR, DSC and TG results suggested that intermolecular hydrogen bonds were formed between SF and PCL molecules in the blends. Homogeneous morphology of blends was illustrated by SEM micrographs.