The sodium salts in black liquor exists in two main forms: as phenolic sodium (—CONa) and carboxylate sodium (—COONa) groups (PCSG) forming a part of alkali lignin or as dissolved salt (NaOH and Na2CO3). The purpose of this study is to investigate the effect of inorganic and organic bound sodium on the char characteristics of alkali lignin, char samples were prepared by a hightemperature furnace as pyrolysis temperature at 400℃, 600℃ and 800℃, respectively. The char morphology, elemental distribution, gasification reactivity and catalytic mechanism were studied by scanning electron microscopy/energy spectrum analyzer (SEM/EDS), thermal gravimetric analysis (TG) and thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TGA-FTIR). The results suggested that for organic bound sodium lignin, a large number of bubbling occurred at the char surface and the sodium content of char surface was increased from 5.36% to 15.72% as the pyrolysis temperature was increased from 400℃ to 800℃. Meanwhile, the carbon conversions of CO2 and steam gasification were increased by 30% and 20%, respectively. The effect of organic bound sodium on the reaction characteristic was varied with temperature. When the reaction temperature was lower than 600℃, the reaction mainly occurred between —CO2Na and char. As the temperature was in the range of 600~800℃, both —CO2Na and —CONa can react with char. As the temperature was higher than 800℃, the reaction mainly occurred between —CONa and char.