We have studied the photodetachment from molecular oxygen anion O-2(-) leading to eleven O-2 electronic states. Both single-and multichannel scattering calculations were performed using the Schwinger variational method with the Hartree-Fock or configuration interaction approximations for the target states. Our calculated total cross sections agree well with the existing experimental data. One Feshbach resonance was found at about 5 eV above the photodetachment threshold. This resonant state has the character of the 1 pi (3)(u)1 pi (4)(g) configuration, and decays to several final channels. Our calculated partial cross sections suggest that shape resonances exist in different channels at higher energies, and the structures of these shape resonances differ from what we have seen in the photoionization from neutral molecules. The most significant feature in this photodetachment process is the channel coupling effect due to electron correlation.