By using molecular dynamics simulations based on the classical mechanic method, the dispersion behavior of gasoline detergent in deposit aggregation system was investigated. The representative simulation relating to the deposit molecules and the gasoline detergent molecules with high market share were selected as the model compounds. The microscopic mechanism of dispersing function of gasoline detergent was revealed in detail. It was found that due to Einterac(depo-depo)>Einteraction(gaso-gaso)>Einteraction(gaso-depo), the deposits were driven to gradually aggregate themselves in the gasoline medium. The relative strong interaction between characteristic groups in detergent molecules and deposits could weaken the interaction between deposit aggregates, which mainly comes from the Van der Waals force, the electrostatic interaction, and the orbital interaction. In order to play the dispersing role of detergent, the main factor is to enhance the interaction between the gasoline detergent and the deposit appropriately from the viewpoint of molecular structure design.