High spin states in 188Tl have been investigated via the 157 Gd(35Cl,4n) reaction at beam energy of 170 MeV. A rotational band built on the πh9/2 (×) vi13/2 configuration with oblate deformation has been established. Considering the similarity between the band structure observed in odd-odd Tl nuclei, spin values have been tentatively proposed for the new band in 188Tl. The πh9/2 (×)vi13/2 oblate band in 188Tl shows low-spin signature inversion,and it can be interpreted qualitatively by the two quasiparticle plus rotor model including a J-dependent p-n residual interaction.