Abstract: The physicochemical properties of Shenhua coal gasification slag were characterized with the aids of XRF, XRD and SEM/EDS, and the catalytic effect of gasification slag on petroleum coke/CO2 gasification reactivity was also investigated. The results showed that the ash contents of bottom slag and fly ash were 7839% and 6271%, respectively. Bottom slag contained higher contents of Ca and Fe, but lower contents of Si and Al than those of fly ash. Inorganic matters in gasification slag mainly existed in the form of inert materials with no gasification reactivity. Calcium sulfate, iron oxide and glaserite(K3Na(SO4)2) in bottom slag were main catalytic components, while there was only low content of calcium sulfate in fly ash with catalytic effect. With increasing addition of slag, carbon conversion versus maximum gasification reactivity decreased. Catalytic gasification reactivity of petroleum coke with 5%-30% addition of gasification slag was raised 2-7 times as compared with noncatalytic one, and bottom slag had higher catalytic activity than fly ash.