Biomass gasification appears as a potential source of renewable and sustainable energy for green environment. Biomass steam gasification has gained significant importance in this era due to high product yield and economical viability. For commercialization of biomass steam gasification process, suitable catalyst for tar reduction, higher product yield and active life of catalyst are still hot questions. Different types of catalyst like dolomite, alkaline metal, nickel and olivine are used in biomass steam gasification. Some of them have good potential for tar elimination and others are good in higher product yield. Most of the catalysts have short active life, expensive and with regeneration problem. The purpose of current study is to review the effect of different catalysts in the biomass steam gasification process used for tar elimination and higher product yield. In addition, the potential of coal bottom ash as a substitute of catalyst in biomass steam gasification is discussed. © 2017 Elsevier Ltd