Nowadays, polyurethane foams play a key role in widespread applications, and their market demand is still growing globally. This work aims to prepare hydroxyl telechelic liquid natural rubber, a bio-based polyol, as a sustainable raw material and to enhance elastic properties of soft segment bio-based polyurethane foams. A hydroxyl telechelic liquid natural rubber with a viscosity-average molecular weight of 4.2 x 10³ g/mol was successfully produced by oxidative degradation of natural rubber with hydrogen peroxide in the presence of supercritical carbon dioxide, then modifying the chain-end functionality to obtain hydroxyl number of 59 mg KOH/g. The functionality of hydroxyl telechelic liquid natural rubber was confirmed by FT-IR and ¹H-NMR. Bio-based polyurethane foams were then prepared by mixing the synthesized hydroxyl telechelic liquid natural rubber with commercial diisocyanate. Morphological properties and thermal stability of polyurethane foams were investigated.