The invention discloses marine fuel oil and a production process and device thereof. The marine fuel oil and the production process and device thereof have the advantages that the marine fuel oil is produced by blending FCC slurry, coal tar, catalytic diesel oil, methanol, ethanol, shale oil, vacuum residue and auxiliaries according to a certain proportion, the main indexes of the blended oil meet the quality requirements on 180# marine fuel oil in national standards (GB 17411-2015), the production is performed by using cheap raw materials which are easy to obtain, raw material cost is lowered to the maximum extent, multiple components of the marine fuel oil can replace one another and can be flexibly selected according to market quotations, and the adverse effect caused by raw material price fluctuation can be relieved; the blended oil is purified by a static separation manner, fine solid catalyst particles can be removed, a static separation device is improved, a traditional double-electrode separation manner is abandoned, static separation efficiency is increased effectively, the adding quantity of the relatively-cheap FCC slurry is increased, and raw material cost is reduced; by a three-electrode design, the utilization rate of device internal space is increased.