In the present study calculations of con-elation energy on the ground state 2S of Liatom has been examined .The ground state energy was calculated for both uncorrelated (HF) and correlated wave functions. Configuration-Interaction method used to study the correlation effect, where correlated wave function of Weiss (1961) with correlated two-particle density of Al-Bayati (1984) was used. The analysis of calculations has been achieved by using partitioning technique which partitioned the correlated two-particle density into the pair wise components KaKβ ,KaLa and KβLa . The resultant correlation energy for whole Li-atom was found to be (-0.03141a.u.) with percentage correlation energy equal to (69%). Moreover, some radial properties such: one and two-particle radial density distribution functions and their changing, the inter-particles radial distribution function and its changing, the one, two and inter-particle expectation values, the one and inter-particle standard deviations has been examined. Also some magnetic properties such: nuclear magnetic shielding constant and diamagnetic susceptibility has been achieved.