The invention relates to an organic fertilizer drum granulation process and an organic fertilizer drum granulation production line. In the production process of the organic fertilizer drum granulationprocess disclosed by the invention, returning charge and new materials are separately conveyed into a cylinder of a drum granulator, and the returning charge is humidified and combined with the new materials in the cylinder to grow and form organic fertilizer granules of suitable granularity. Since the returning charge and new materials are separately added, the returning charge and the new materials are separated in a granulation path in the cylinder, the granules in the returning charge are combined with the new materials to form granules, and the residual partial new materials are separately combined into granules. Therefore, the granule size can be controlled by controlling the ratio of the returning charge and new materials, so that the yield of the organic fertilizer granules is increased.