We have obtained rotationally resolved pulsed field ionization photoelectron (PFI-PE) spectra of O2 in the energy range of 20.2-21.3 eV, covering the ionization transitions of O2⁺(B ²Sigmag^-, upsilon+ = 0-7, N⁺) <--O2(X ³Sigmag^-, upsilon " = 0, N "). Only the Delta N = -2, 0, and +2 (or O, Q, and S) rotational branches are observed in the PFI-PE bands for O2⁺(B ²Sigmag^-, upsilon⁺ = 0-7), indicating that the outgoing electron continuum channels with angular momenta l = 1 and 3 dominate in the ionization transitions. This experiment allows the determination of accurate spectroscopic constants, such as ionization energy (20.29825 +/- 0.0004 eV) for the formation of O2⁺[B ²Sigmag^-, upsilon⁺ = 0, N⁺ = 1 (F2)] from O2(X ³Sigmag^-, upsilon " = 0, N " = 1), vibrational constants (omegae⁺ = 1152.91 cm^-1, omegae⁺chie⁺ = 20.97 cm^-1_, and rotational constants (Be⁺ = 1.255 +/- 0.0015 cm^-1, alphae⁺ = 0.0241 +/-0.00037 cm^-1_ for O2⁺(B ²Sigmag^-, upsilon⁺ = 0-6) are measured to be approximate to 0.2-0.6 mu s, which are significantly shorter than those of approximate to 1.9 mu s observed for O2⁺(b ⁴Sigmag^-, upsilon⁺ = 0-5). The shorter (nominal) effective lifetimes for high-n Rydberg states converging to O2⁺(B ²Sigmag^-, upsilon⁺ = 0-6) are attributed to the higher kinetic energy releases (or velocities) of O⁺+O fragments resulting from predissociation of the O2⁺(B ²Sigmag^-, upsilon⁺ = 0-6) ion cores. Rotationally resolved PFI-PE measurements also make possible the identification of the weak vibrational progression with the origin at 20.35 eV as associated with transitions to O2⁺(²Sigmau^-, upsilon⁺ = 0-7). The analysis of the rotationally resolved PFI-PE bands for O2⁺(²Sigmau^-, upsilon⁺ = 0 and 1) has yielded accurate rotational constants and IE values for these states. The rotational structures resolved in the O2⁺(²Sigmau^-, upsilon⁺ = 0 and 1) PFI-PE bands are contributed overwhelmingly by the Delta N = -3, -1, +1, and +3 (or N, P, R, and T) rotational branches, showing that the angular momenta for the outgoing photoelectron are restricted to l = 0, 2, and 4. Based on simulation of the observed rotational structures, we also obtain the predissociative lifetimes for O2⁺(B ²Sigmag^-, upsilon⁺ = 0-7) and O2⁺(²Sigmau^-, upsilon⁺ = 0-7) and O2⁺(²Sigmau^-, upsilon⁺ = 0-1) to be in the range of 0.45-2 ps.