Biomass as a renewable and sustainable energy source is expected to solve the energy crisis problem. Ulin wood residues as a biomass source could be converted into bioenergy utilizing the pyrolysis process since its primary component is a hydrocarbon. Pyrolysis process has received many interests for bioenergy production from biomass, elevating the importance of the kinetic study of pyrolysis. The kinetic study of pyrolysis is related to the beginning stage behavior of gasification and combustion process. The kinetic mechanism of pyrolysis is analyzed using Thermogravimetry Analysis (TGA), by estimating the mass decomposition at solid-state that shows TG and DTG curve. The TG and DTG curves were analyzed to see the effect of heating rate on decomposition temperature. This experiment was performed by heating 10 mg of Ulin wood sawdust from ambient temperature to 1473 K utilizing 100 mL/min of nitrogen (N 2) gas as carrier gas at various heating rate: 5, 10, 20, and 50 K/min. The kinetic parameters were determined by applying the iso-conversional methods, the Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods, and then compared the results with the non iso-conversional method, using Kissinger method. The average value of activation energy calculated using the KAS and FWO methods are 253.5514 and 245.2512 kJ/mol, with the average value of constant coefficient square (R 2) of 0.9848 and 0.9859, respectively, whereas the calculated activation energy and R 2 using the Kissinger method are 237.4478 kJ/mol and 0.8520, respectively.