Overflow metabolism can be explained by a pathway switch behavior in the cell based on the tradeoffs between metabolic efficiency and proteomic efficiency(enzymatic kinetics). This thesis simulates this behavior on the both small-scale and genome-scale model. By sweeping the enzyme kinetics parameters on multiple pathways or reactions, the simulation could potentially approach the experimental results, however, would converge to some bounds beyond. Therefore, hypotheses of some extra constraints, such as the limitation of oxygen uptake ,electron transport chain, as well as the function of motility protein are presented.