Abstract: Dissipative Particle Dynamics (DPD) method was used to study the adsorption properties of polyacrylicacid (PAA) and polyethylene glycol (PEG) compound additives on the surface of dicalcium silicate. in order to reasonably characterize the interaction between polymer and dicalcium silicate surface, mesoscopic polymer-surface interactions are determined by matching the surface excess, as computed with atomistic molecular dynamics (MD), with those for DPD, thus realizing a coupling between the mesoscopic and atomistic scales. The results showed that the optimal ratio of compound additive is 5:5, which features better adsorption effect, water displacement ability and self-adsorption stability than that of single PAA or PEG additive. in the adsorption process of PAA₅:PEG₅ composite additive, there is a synergistic effect between polymer PAA and PEG, which makes it the best inhibitor for decomposition of dicalcium silicate.