As a method for the effective removal of aerosol particles, acoustic agglomeration technology has been widely used in the field of dust removal and defogging. In this study, a coupled Computational Fluid Dynamics and Discrete Element Method model was developed to investigate acoustic agglomeration performance of aerosol droplets in a high-temperature and high-pressure environment. A four-way coupling strategy including flow-parcel and inter-parcel interactions was fully considered. A simple parcel-parcel interaction model was introduced with an elastic coefficient calibrated as 1 x 10(-14) kg.s(-2). A comprehensive investigation focused on determination of the agglomeration characteristics of droplet aerosols under the action of acoustic waves. The acoustic wave significantly influences the agglomeration behavior of aerosol droplets by changing the acoustic pressure structure in an agglomeration chamber and changing the acoustophoretic force exerted on the droplet. The environmental parameters of operating pressure and ambient temperature indirectly affect the interaction processes of transient flow and aerosol droplets. In general, the results showed better aerosol agglomeration performance in high-temperature and high-pressure environments. (C) 2019 Elsevier B.V. All rights reserved.