Abstract A three-dimensional method for the stochastic simulation of dendritic growth of polydisperse aerosol particles on a fiber was proposed and its capability was demonstrated for the case of convective diffusion ( Pe = 200-25000, R = 0.1,0.2, σ g = 1.1, 1.2, 1.4). Based on the simulation result, time dependency of the morphology of particle dendrites and the collection efficiency were investigated. Particle dendrites on a fiber simulated by the proposed method grew up three-dimensionally and also randomly, and were similar to those in actual filters. The average distribution of the deposited particles on a fiber was largely dependent on the Peclet number, Pe, and interception parameter, R, but not so much on the deposited mass of particles nor on the polydispersity of aerosol particles. Furthermore, the maximum deposition of particles appeared at a certain angle from the front stagnation point and shifted to a larger angle as Pe increased but did not change so much even if the mass of deposited particles increased. A single fiber collection efficiency at zero dust load agreed well with the analytical solution, and that of a dust loaded fiber increases almost linearly with the loaded mass of deposited particles in a unit filter volume, m, regardless of filtration conditions. The coefficient in the linear function or the collection efficiency raising factor Δ increased as Pe increased and R decreased. However, values of Δ did not show a clear tendency by the change of geometric standard deviation of particle size σ g. Most of the conclusions obtained in this study were almost the same as those obtained for monodisperese aerosols although the measure of polydispersity of aerosol particles, the logarithmic standard deviation σ g, varied from 1 to 1, 4. Therefore, it could be concluded that in the studied range of σ g the polydispersity of aerosol particles does not affect the average performances of the dust loaded filter.