Abstract: Abstract: The emission of particulate size distribution characteristics on biomass solid fuel in the process of combustion had not been clear. And the effects that burning power and air content on the particle distribution had unknown. So the particulate emission of corn straw, cotton stalks and wood, three kinds of solid biomass fuel, was researched on biomass combustion test platform with Electrical Low Pressure Impactor(ELPI) in this paper. The solid biomass fuel which was manufactured and developed by Chinese Academy of Agricultural Engineering was compressed into a cylindrical type, diameter 8mm, length 10~30mm. In laboratory platform, three kinds of biomass fuel were burned, and at the same time the feeding quantity was controlled to adjust the burning power. Waste gas and particle distribution at the power of 10kW, 12Kw, 14kW, 16K and 18kW was measured respectively. When each kind of power in stable, measuring and recording waste gas and particle distribution in 30 minutes. Then finding that at the power of 14kW,particle emission of three kinds of fuel was the least. So at the power of 14kW,controlling air intake, respectively measuring particles distribution of emissions in 6m/s, 7m/s, 8m/s three kinds of wind speed. When combustion in stable, waste gas and particle distribution was measured and recorded in 30 minutes at each wind speed. The measuring instrument, ELPI, which divided particles into 12 grades, from 0.003～10μm, can record of each class of particle number and mass instantaneously. It focused on the particles' number concentration distribution and mass concentration distribution of three kinds of biomass forming fuel. The results showed that the peak particle number concentration of three kinds of fuel mainly concentrated in 4,5,6,7 levels, which were more than 70% in total number of particulate matters. The peak particle mass concentration concentrated in 7 and 12 level which were more than 50% in total mass of particulate matters. Power increased, particulate matter emissions decreased first and then increased, crude membrane particles matter increased. The proportion of PM2.5 in the particles reduces 10%~20% along with the power added. PM emission was lowest at the power of 14KW.Air Increased, PM decreased, but distribution trend remained unchanged. When excess air ratio was 1.5~1.7, the combustion of three kinds of solid biomass fuel was best, and the particulate matter was least.（英文未粘）