The all electron full potential linearized augmented plane wave method has been used for all ab initio theoretical study of the band Structure, density of states and electron charge density, and the spectral features of the linear and nonlinear optical susceptibilities for the host CuSn and Li2CuSn compounds. We have calculated the density of states at Fermi energy and the electronic specific heat coefficient (gamma). The total charge densities in the (100) and (110) planes were calculated. We noticed that inserting Li into CuSn leads to give two structures in the spectral features of the linear optical Susceptibilities while the host compound gives only one structure. Insertion of Li into CuSn leads to breaking the symmetry resulting in noncentrosymmetric material. We have calculated the complex second-order nonlinear optical Susceptibility tensor for the intercalated Compound.