The Catallytic activity of various mixtures of alkali salts(k2CO3, K2SO4, Na2CO3), iron salt(FeSO4) and alkaline earth metals(CaCO3 and two limestones)on steam-char gasification at 700-800 has been measured in a thermobalance reactor. THe melting behavior of the mixed salts at the reaction atmosphere has been investigated. The gasification rate with alkali salt could be enhanced by the addition of iron salt and the largest effectiveness of the mixed salts on the gasification rate can be attainde at 800. In the gasification of subbituminous char with(K2SO4+FeSO4) and semi-anthracite char with(Na2CO3+FeSO4)exhibit better catalytic activity than those with K2CO3. The gasification rate with Na-Fe-Ca mixed systems strongly depends on calcination rate of the Ca-based additives. A kinetic parameter is proposed as a simple measure of activity of various catalysts based on the grain model.