Ab initio calculations have been performed to study on the molecular structures and the vibrational levels of the low-lying ionic states ((2)A(2), B-2(1), (2)A(1), and B-2(2)) of pyrrole. The equilibrium molecular structures and vibrational modes of these states are presented. The theoretical ionization intensity curves including the vibrational structure of the low-lying two ionic states are also presented and compared with the photoelectron spectrum. A number of new assignments of the photoelectron spectra are proposed.