The carbonization of palm fiber with a muffle furnace was investigated by thermogravimetric analysis. The experimental results showed that palm fiber char has better combustion properties than those of palm fiber. The palm fiber char yield decreases with the increase in carbonization temperature. From 200 °C to 300 °C, the mass loss rate of palm fiber char is 45.97%. As the carbonization temperature increases, the high heat value of palm fiber char increased by 41.39%. The palm fiber char exhibited lower moisture and volatile, higher energy density and heating value. With the rise in temperature, the H/C and O/C decreased from 14.31 and 76.01 to 0.15 and 5.80, respectively. As the carbonization temperature increases, the ignition temperature and the average combustion rate increase, accordingly. The maximum combustion rate of the palm fiber char at 400 °C is 2.87 mg/min. The comprehensive combustion index increases by approximately 12 times from 200 °C to 400 °C.