The steam gasification of wheat straw black liquor char (BLC) was studied in a laboratory-scale tube furnace at temperature from 750℃ to 900℃. The impacts of temperature and causticizing agent TiO2 on characteristics of gas and solid product during gasification process were investigated. Influence of TiO2 on weight loss characteristics of BLC was also studied by thermo gravimetric analyzer at temperature 850℃.Results showed that at temperature from 750℃ to 900℃, with TiO2 addition, the relative concentration of CO2 increases by about 5% while the relative concentration of H2 decreases by about 5% in gas product, at the same time the gas heating value reduces by about 7%; however, carbon conversion rate increases by about 10% without melting of char in the gasification process;temperature has no significant effect on the composition of the solid product. Furthermore, TiO2 changes the partition of Na and Si in char. TiO2 not only reacts with Na2CO3 to form Na2O〖DK〗·nTiO2, but also combines with Na2SiO3 to generate Na2TiSiO5.