Abstract: Bubble scrubbing is a typical retention process for radioactive aerosol in severe accident scenarios and mitigation measures of nuclear power plants. It is indispensable to evaluate the removal characteristics of aerosol under bubble scrubbing condition, which plays a critical role for the evaluation of source term and the formulation of corresponding mitigation measures. For the background of polydisperse aerosol removed by bubble scrubbing, the particle size distribution was assumed to satify a log-normal distribution in this study. Brownian diffusion, gravity sedimentation and inertia impaction were chosen as the dominant removal mechanisms. The analytical correlations between the three distribution parameters of particle size distribution (N, d_pg, σ_g) and their initial values, bubble rise height and deposition coefficient were derived by moment method. Compared with the exact solution, the analytical solution shows good prediction accuracy. The analytical solution presented in this paper can be used to quickly evaluate the removal characteristics of aerosol without the detailed information of particle size distribution but only some initial distribution parameters.