Abstract: The formation mechanism of soot particles in biomass combustion was introduced.It mainly included the various formation routes of biomass soot particles,the intermediate product polycyclic aromatic hydrocarbons( PAHs) of biomass soot particles,and the intermediate products polycyclic aromatic hydrocarbons to produce biomass soot particles.The influence of polycyclic aromatic hydrocarbons,reaction atmosphere,and reaction pressure and reaction temperature on the formation of soot,and the effect of metal ions on the formation of soot and soot growth process were analyzed.The shortcomings of the existing research on the formation mechanism of soot particles were summarized.The research of the intermediate products of biomass soot and the first and two formation mechanism of biomass soot,as well as the various factors of generation quantity of biomass soot should be systematically studied.formation mechanism of biomass soot was analyzed by using quantum chemical theory,moment and laser detection experiments,and it can learn from the formation mechanism of coal-fired soot and diesel soot formation mechanism and experiment research method.The formation mechanism of biomass soot should be discussed by the thermodynamics,dynamics theory,the evolution of nucleation,and the influencing mechanism. From the perspective of chemical reaction and engineering thermophysics,the evolution behavior of formation mechanism of soot particles and the growth behavior process of biomass soot nuclei can be deeply studied,and reasonable formation mechanism of biomass soot can be obtained.the.This study provides the theoretical and practical guidance for the practical engineering application of reducing the environmental impact of smog.