Abstract: Biomass ashes were prepared from three rich in alkaline and alkaline earth metal materials, viz., wheat straw (WS), sea grape (SG) and ixeris chinensis (IC), at different temperatures of 500, 600 and 815℃; the catalytic effect of biomass ash on the hydro-gasification of Shenfu coal (SF) char was then investigated. The results show that the ash yield and the content of alkali metals and chlorine reduce with increasing ashing temperature from 500 to 815℃; significant ash melting can be observed at high temperature near 815℃. The biomass ashes obtained at 600℃ exhibits the best catalytic effect on the gasification of coal char; the more the ash is loaded with the char, the stronger exhibit the promoting effect on the gasification is. The ash from IC performs best in catalyzing the coal char gasification, whereas the SG ash is the worst catalyst. The high content of silica in the WS ash and the high content of chlorine in the SG ash may explain their poor catalytic effect on the char gasification; chlorine can aggravate the volatilization of alkali metal and lead to a severer inhibiting effect on the coal char hydrogasification than silica with the same molar quantity.