Polyurethane has a characteristic of having urethane functional group on its main polymer chain. The amount of world polyurethane use in 2010 estimated about 5% of world's total plastic consumption. One of methods for forming polyurethanes is pre-polymer termination using diisocyanate, and the second one is polyol termination using diisocyanate and then followed by adding a crosslinker. Biomass material is known for having high hydroxyl group content so that it can be used as a crosslinker in the polyurethane manufacturing process. Indonesia as tropical country is known for its abundant diversity and availability of biomass material therefore the use of biomass material as crosslinker can increase the value of biomass material in Indonesia. Therefore, in this study hybrid biomass based bio-polyurethane foam was fabricated by reacting the biomass materials with polyurethane. The synthesis of the hybrid biomass based polyurethane-bio foam used Toluene Diisocyanate 80 (TDI 80) and Polypropylene Glycol 2000 (PPG 2000), and then the variation of biomass was added to the reaction. Various kind of biomass material of 21 grams was used as variables of the samples. In this study, the crosslinking network forming in the hybrid bio-polyurethanes was confirmed by FTIR. FTIR spectra showed that the hydroxyl groups from biomass were not detected in the hybrid bio-polyurethanes because the biomass hydroxyl groups were bond with polyurethane to formed crosslinking network. The thermal properties of hybrid biomass based bio-polyurethane foam also investigate using simultaneous thermal analyzer (STA). Based on STA, hybrid biomass based bio-polyurethane foam had good thermal stability and lower melting temperature and glass transition temperature than virgin polyurethane foam. The addition of biomass material can increase the occurrence of crosslinking with polyurethane material through the formation of hydrogen bond reactions thereby increasing the thermal stability of the material.