The viscosity and solubility of ethanol/diesel fuel blends have an important influence on its application in diesel engines. Molecular dynamics simulation was employed to study the effects of different alcohol additives on the viscosity and solubility of the blends between diesel and anhydrous ethanol. Among these alcohols, n-butanol, n-heptanol and n-decanol were selected for investigating the influence of alcohol chain length on solubility and viscosity. The results showed that the viscosity of the blends increased with the increasing of alcohol carbon number. The analysis of diffusion coefficient represented that the alcohol additives enhanced the molecular mobility and activity, and energy analysis indicated that alcohols with higher carbon numbers provided a better inter-soluble capacity. Taking these factors into account, n-heptanol can be recommended as a co-solvent additive for ethanol/diesel system due to the acceptable fuel properties and soluble performance.