Hyperfine structure spectrum in 56908nm line of 141Pr+ was measured by the collinear fast-ion-beam laser spectroscopy- All the spectral lines were resolved- The magnetic dipole and electric quadruple coupling constants, and hyperfine splitting of the metastable levels and excited levels were determined- Our results were in agreement with the published data within experiment uncertainty- The accuracy of the magnetic dipole coupling constants was improved by one order of magnitude compared with the published data-