Recently, the material market was increasingly extended with the dramatic development of electronic equip-ment such as wearable electronic devices with increasing demand. Polyurethane (PU), which is in general use in many fields, have outstanding mechanical property, wear resistance, and chemical resistance, therefore, it can be utilized as protective film material for electronics when the transparency of PU is highly increased. In this study, two types of bio-polyols and two types of prepolymers are synthesized to improve transparency of PU, and then, they were used to prepare PU films in order to confirm the effect of different chemical structures in PU films. Nuclear magnetic res-onance and Fourier transform infrared confirmed the chemical properties of bio-polyol and bio-PU, and thermal, mechanical, and optical properties were analyzed by using thermogravimetric analysis, differential scanning calorim-eter, universal testing machine, and ultraviolet-visible spectrophotometer. The bio-PU films show thermally stable properties and high transmittance about 87%.