A microscopic visualization system was constructed to observe the movement and capture of particles around a charged single droplet under electric and acoustic field. Ash from Banshan Power Plant was used as representative particles. A laser particle size analyzer was used to verify the effect of agglomeration. The experimental results show that the inertial capture can be changed to attraction dominated by electrostatic forces (dielectrophoretic force, Coulomb force) by charging the droplet, and particle deposition on the surface of droplet changes from dendritic to tightly stacked. The trajectories of particles show reciprocating vibrations when adding acoustic field. The electrostatic force and liquid bridge force introduced by the charged droplets can enhance the internal adhesion of agglomerates. Further particle size distribution experiments show that both charged droplets and sound waves can effectively promote the agglomeration of particles.