An organic electrolytic solution and a lithium battery employing the same are provided. The organic electrolytic solution includes: a lithium salt; an organic solvent containing a high dielectric constant solvent and a low boiling point solvent; and an additive comprising a crotonate derivative including a substituted silyl group. The organic electrolytic solution and the lithium battery employing such an electrolytic solution suppress a reduction decomposition of a polar solvent and decrease irreversible capacity in the first cycle. Thus, the charge/discharge efficiency, lifespan, and reliability of the battery can be improved.