The photoionization detection method is employed to systematically study the odd-parity bound-excited states of Sm atom. Three different excitation paths are designed to carry out three-step excitation and photoionization processes for the Sm atom in the same energy region. By scanning the wavelength of third-step dye laser not only the level energies of a large number of odd-parity bound-excited states are determined, but also the information about relative intensity of the corresponding transition is obtained. Comparison of the three groups of spectra corresponding to the three paths enables us to assign the J-value, the total angular momentum of the excited states of Sm atom uniquely. In addition, a small number of level energies measured with different methods previously are also confirmed in this work.