Spinnable mesophase pitch precursor containing more than 98% mesophase content was successfully prepared from FCC-DO (fuid catalytic cracking-decant oil) without hydrogenation or catalytic reaction. The preparation method involved thermal condensation, vacuum treatment, and annealing treatment. Petroleum mesophase pitch-based carbon fbers are produced by melt spinning of pitch precursors, followed by stabilization and carbonization. The resulting carbon fber exhibited good mechanical performances up to tensile strength of 2.1 GPa and tensile modulus of 212 GPa, with strain-to-failure higher than 1.0%. These properties ensuring that the automotive grade carbon fbers can be successfully prepared from FCC-DO derived petroleum mesophase pitches through the cost-competitive processes.