The mass loss characteristic of corncob acid hydrolysis residue (CAHR), corncob and lignin isolated from CAHR (CAHL) were analyzed by using a thermal-gravimetric analyzer (TGA). The evolution of main volatile products pyrolyzed from CAHL was characterized by TGA coupled to Fourier transform infrared spectrometry (TGA-FTIR). Pyrolysis behavior of CAHR and corncob was then investigated on a self-designed pyrolysis apparatus, furthermore, component of pyrolysis gas and char reactivity were also examined. Results of TGA showed that an abrupt mass loss stage for corncob was observed within narrow temperature zone from 250℃ to 450℃, while the CAHR and CAHL decomposed gradually from 180℃ to 800℃. It was indicated by TGA-FTIR that methanol and phenols were released at low temperature of 200～420℃, and that CO and CO2 mainly released after 400℃. The char yield (30.35%～42.64%) from CAHR at 550～850℃ was much higher than that (19.18%～26.40%) from corncob, and CO2 gasification reactivity of CAHR char was lower than that of corncob char. The yield of CO, CO2 was higher compared with that of H2 and CH4, and H2 yield was notably enhanced at pyrolysis temperature over 650℃.