On-aim control of protein adsorption onto a solid surface remains challenging due to the complex interactions involved in this process. Through computational simulation, it is possible to gain molecular-level mechanistic insight into the movement of proteins at the water-solid interface, which allows better prediction of protein behaviors in adsorption and fouling systems. In this work, a mesoscale coarse-grained simulation method was used to investigate the aggregation and adsorption processes of multiple 12-Ala hydrophobic peptides onto a gold surface. It was observed that around half (46.6%) of the 12-Ala peptide chains could form aggregates. 30.0% of the individual peptides were rapidly adsorbed onto the solid surface; after a crawling process on the surface, some of these (51.0%) merged into each other or merged with floating peptides to form adsorbed aggregates. The change in the solid-liquid interface due to peptide deposition has a potential influence on the further adsorption of single peptide chains and aggregates in the bulk water. Overall, the findings from this work help to reveal the mechanism of multi-peptide adsorption, and consequentially build a basis for the understanding of multi-protein adsorption onto a solid surface.