Char and soot characterization was performed on samples obtained from pilot-scale entrained flow gasification of coal bio-oil slurry (CBS) and coal/water slurry (CWS) at different operating conditions. The compositions and gasification reactivity of char and soot have been investigated to reveal the difference of CBS and CWS slurries. The results show that both char and soot obtained from CBS gasification contain alkali and alkaline earth metals which come from the bio-oil. These CBS char and soot alkali-containing samples exhibit higher gasification reactivity than those from CWS gasification. For CBS gasification, soot has higher gasification reactivity compared with char. The gasification reactivity may be caused by the catalytic effect of KCl and K(2)SO(4 )existing in char and soot. The reactivity of char and soot is also influenced by the gasification conditions (such as H2O/C ratio), and high CO2 gasification reactivity is observed for chars exposed to high H2O/C ratios in the entrained flow reactor.