Abstract: Co-gasification of coal and biomass, as one of the means to achieve efficient and clean utilization of coal, has a positive contribution to achieving carbon neutrality and carbon peaking. Co-gasification not only helps to overcome a series of problems derived from coal gasification alone, reduces the emission of SO_x, NO_x and other harmful substances, and improves coal reactivity but also helps to overcome the problems of low energy density, poor gasification efficiency and high tar yield existing in biomass gasification alone. Based on this, the progress in the research of influencing factors and synergetic reaction mechanism is reviewed in this work. The effects of feedstock type and pretreatment method, process parameters and gasifier type on the co-gasification process are summarized, the catalytic synergistic mechanism in the co-gasification process of coal and biomass is systematically described, the synergistic mechanism of non-catalytic factors in the co-gasification process is briefly outlined, and new methods to study the co-gasification process are comprehensively discussed. The main concern of the co-gasification process is sorted out, and prospects are made for constructing the synergistic pathway with the help of the new in situ technique and revealing the reaction mechanism in coupling the chemical reaction system with the combination of density functional theory and gasification dynamics models.