Abstract: Taking Populus tomentosa as an example, a methodology called elutionweighingparticle sizeanalysis (EWPA) was proposed to evaluate quantitatively the ability of retaining fine particulate matter (PM_2.5, diameter d≤2.5 μm) and atmospheric particulate matter by plant leaves using laser particle size analyzer and balance. This method achieved a direct, accurate measurement with superior operability about the quality and particle size distribution of atmospheric particulate matter retained by plant leaves. First, a preexperiment was taken to test the stability of the method. After cleaning, centrifugation and drying, the particulate matter was collected and weighed,  and then its particle size distribution was analyzed by laser particle size analyzer. Finally, the mass of particulate matter retained by unit area of leaf and stand was translated from the leaf area and leaf area index. This method was applied to a P. tomentosa stand which had not experienced rain for 27 days in Beijing Olympic Forest Park. The results showed that the average particle size of the atmospheric particulate matter retained by P. tomentosa was 17.8 μm, and the volume percentages of the retained PM_2.5, inhalable particulate matter (PM₁₀ , d≤10 μm) and total suspended particle (TSP, d≤100 μm) were 13.7%, 47.2%, and 99.9%, respectively. The masses of PM_2.5, PM₁₀, TSP and total particulate matter were 8.88×10^-6, 30.6×10^-6, 64.7×10^-6 and 64.8×10^-6g·cm^-2, respectively. The retention quantities of PM_2.5, PM₁₀, TSP and total particulate matter by the P. tomentosa stand were 0.963, 3.32, 7.01 and 7.02 kg·hm^-2, respectively.