Abstract: The gasification reactivities of chars generated from the pyrolysis of corncob and its acid hydrolysis residue (AHR) were investigated by using a thermal gravimetric analyzer (TGA). The effects of pyrolysis temperature, heating rate, gasification temperature and gasification agent (CO₂ and H₂O) on the gasification reactivities were examined, and the char morphology was characterized by means of scanning electron microscopy (SEM). The results show that the AHR char performs lower gasification reactivity than the corncob char does in both steam and carbon dioxide. The gasification reactivity of AHR char decreases with increasing the pyrolysis temperature from 550 to 850 ℃, but increases when the pyrolysis heating rate increases from 0.1 to 15.0 K/s. The gasification reactivity of AHR increases with increasing temperature, and the steam gasification reactivity of AHR char is higher than the CO₂ gasification reactivity at gasification temperatures between 850 and 950 ℃. The gasification kinetic parameters based on a mixed reaction model were calculated.