Angle-resolved photoemission spectroscopy (ARPES) and torque magnetometry (TM) measurements have been car-ried out to study the electronic structures of a correlated topological insulator (TI) candidate YbB6. We observed clearsurface states on the [001] surface centered at the (Γ) and (M) points of the surface Brillouin zone. Interestingly, the fermiol-ogy revealed by the quantum oscillation of TM measurements agrees excellently with ARPES measurements. Moreover, the band structures we observed suggest that the band inversion in YbB6 happens between the Yb5d and B2p bands, insteadof the Yb5d and Yb4f bands as suggested by previous theoretical investigation, which will help settle the heavy debateregarding the topological nature of samarium/ytterbium hexaborides.