Synopsis With the ab initio calculations, we hve studied the structures of the photoelectron spetra the S2 molecule.Utilizing the complete active space self-consistent field and the internally contracted multireference configuration approach, we calculated the potential energy curves.Not only the core-valence correlation, relativistic corrections and the Davidson modification have been taken into the account, but also we have extrapolated the potential energy curves to the complete basis set limit.According the potential energy curves, the spectroscopic parameters of S2+ molecular ion were fitted, and the vibrational levels and the vibrational wave functions of the several electronic states were determined.Our calculated spectroscopic parameters agree well with existing experimental values.[1-4]Finally, through the Franck-Condon factors which were calculated by the potential enery curves, we obtained the ionization intensity distribution in a range of 9-15 eV, and the adiabatic and vertical ionization energy of the S2 molecule.