The invention relates to a production method of ship fuel oil, which comprises the following steps: heating catalytic slurry oil, filtering through a precision filter to remove tiny catalyst granules in the slurry oil, mixing with hydrogen, heating, contacting the mixture with a residual oil hydrofining catalyst, a distillate hydrofining catalyst and a distillate hydrocracking catalyst to carry out catalytic hydrogenation reaction on the mixture, carrying out gas-oil separation and fractionation on the reaction product to obtain a tail oil fraction, and mixing the tail oil fraction with vacuum residual oil in different proportions to obtain the finished product. Under mild reaction conditions and lower hydrogen consumption, the method provided by the invention can greatly enhance the doping proportion of the catalytic slurry oil in the ship fuel oil by more than 75%, ensures the indexes of metals, ash and the like in the ship fuel oil to be not overproof, greatly increases the calorific value, improves the compatibility of the ship fuel oil, and ensures the production of the high-quality ship fuel oil product.