The present invention relates to an electrolytic solution for a lithium battery and a lithium battery using the same. The organic electrolytic solution includes a lithium salt, a mixed organic solvent comprising a high dielectric constant solvent and a low boiling-point solvent, and an additive. The additive used in the electrolytic solution is a heterocyclic compound of Formula (1): ##STR00001## where R.sub.1, R.sub.2 and R.sub.3 may each independently be a C1-C10 linear or branched alkyl group; R.sub.4 may be a C1-C10 linear or branched alkylene group; X may be a heterocyclic ring containing N and O whereby a tetraallkyl orthosilicate functional group may be linked to N. The lithium battery using the organic electrolytic solution of the present invention is highly reliable and maintains a constant thickness during a charge/discharge cycle.