Abstract: Due to the worldwide demand of primary energy and fossil fuels depletion, biomass fixedbed gasification technology, as the clean and renewable bioenergy utilization technology, attracts an increasing number of researchers. Compared to the updraft fixedbed gasifier, downdraft fixedbed gasifier has the advantage of lower tar content, higher carbon conversion rate, higher calorific value and wider range of usage. This paper presents the reaction during biomass gasification process, classification of downdraft fixedbed gasifiers，research status and prospect of the singlestage and the twostage downdraft fixedbed gasifier.