Co-pyrolysis of coal tar asphaltene (CTA) and biomass is one of the effective ways to realize the utilization of its resource. In this study, corn cob (CB), CTA and CB + CTA were heated to 700 ℃ at 600 ℃/min by TG and Py-GC/MS, respectively. In addition, the functional groups, the apparent morphology, the metal elements distributions and the phase changes were characterized by FTIR, SEM-EDS and Micro Melting Point Apparatus. The results showed that CB + CTA pyrolysis has a synergistic effect, which affected the pyrolysis process and changed the product distribution. In addition, the reaction temperature range and the reaction type of new products were determined by the tar composition distributions during multi-step pyrolysis. The kinetic results of reaction order 1, 2, 3 and 4 showed that the reaction was promoted at low temperatures and inhibited at high temperatures. During the co-pyrolysis process, CTA softened CB by heating, which affected the mass transfer and inhibited the escape of light volatiles from CB, therefore, the reaction temperature and the peak temperature of the maximum weight loss rate move to the high temperature region.