Chemical dispersant, which is a mixture of solvents, surfactants, and other additives, is commonly applied to oil slicks to reduce the oil-water interfacial tension in the event of the oil spill and many chemical engineering processes. In the present study, Computational Fluid Dynamics (CFD) is used to simulate the oil droplet with dispersant applied. The effect of the dispersant is modeled by accounting for the decrease of interfacial tension and dispersant concentration to study the characteristics of the single oil droplet rising in the still water column. The the tip-streaming, which is the process of oil peeling off from the rear tip of the oil droplet, is observed from CFD simulation. The results show that Computational Fluid Dynamics (CFD) method is able to robustly predict the effect of chemical dispersant on the oil droplet, which helps to improve the understanding of the interaction between the oil droplet and the applied chemical dispersant as well as the evaluation of the effectiveness of chemical dispersant.