The potentials for molecular cesium (Cs2) XΣ1+g and AΣ1+u states have been calculated by RKR method. A set of Franck Condon factors for X state (v"=0～30)→A state (v′=0～30) have been obtained by solving radial Schrodinger equation of nuclei. The absorption spectra is demonstrated in the wavelength near 1.06 μm. The calculated absorption spectra are in good agreement with experimental ones.