The symmetry-adapted-duster configuration-interaction method is used to investigate the spectroscopicproperties of ~7Li_2(A~1∑_u~+) over the internuclear distance ranging from 2.4ao to 37ao.The complete potential energycurves are calculated at numbers of basis sets.All the ab initio calculated points are fitted to the analytic MurrellSorbie function and then employed to compute the spectroscopic constants.By comparison,the spectroscopic constantsreproduced by the potential attained at D95(3df,3pd) are found to be very close to the experiments,a~d the values (T_e,D_e,R_e,ω_e,ω_eχ_e,α_e and B_e) are of 1.732 93 eV,1.161 36 eV,0.313 27 nm,251.95 cm~(-1),1.623 cm~(-1),0.005 35 cm~(-1),and0.490 cm~(-1),respectively.With the potential obtained at D95(3df,3pd),the totally 75 vibrational states are found whenJ=0.The vibrational levels,the classical turning points and the inertial rotation constants of the first 68 vibrationalstates are calculated for the first time and compared with the available measurements.Good agreement is obtained.The centrifugal distortion constants of the first 32 vibrational states are also reported for the first time.The reasonabledissociation limit for ~7Li_2(A~1∑_u~+) is deduced using the calculated results at present. The symmetry-adapted-duster configuration-interaction method is used to investigate the spectroscopic properties of ~ 7Li_2 (A ~ 1Σ_u ~ +) over the internuclear distance ranging from 2.4ao to 37ao.The complete potential energy curves are calculated at numbers of basis sets .All the ab initio calculated points are fitted to the analytic Murrell Sorbie function and then employed to compute the spectroscopic constants.By comparison, the spectroscopic constants reproduced by the potential attained at D95 (3df, 3pd) are found to be very close to the experiments, a ~ d the values ​​(T_e, D_e, R_e, ω_e, ω_eχ_e, α_e and B_e) are of 1.73293 eV, 1.161 36 eV, 0.31327 nm, 251.95 cm -1, 1.623 cm -1, 0.005 35 cm -1, and 0.490 cm -1, respectively. Based on the results obtained at D95 (3df, 3pd), the totally 75 vibrational states are found when J = 0. The vibrational levels, the classical turning points and the inertial rotation constants of the first 68 vibrationalstates are calculated for the first time and compared with the available measurements. Good agreement is obtained. The centrifugal distortion constants of the first 32 vibrational states are also reported for the first time. The reasonable disagreement limit for ~ 7Li_2 (A ~ 1Σ_u ~ +) is deduced using the calculated results at present.