Preparation method of biological organic fertilizer

The invention belongs to the technical field of bio-organic fertilizers, and discloses a preparation method of a bio-organic fertilizer. The preparation method comprises the following step of cooling bio-organic fertilizer particles by using bio-organic fertilizer production equipment; the biological organic fertilizer production equipment comprises a cooling bin, a cooling shovel, a cooling motor, a telescopic rod, a plum blossom groove and a sliding block; the cooling bin is provided with an inlet and an outlet, the plum blossom groove is formed in the side wall in the cooling bin, an output shaft of the cooling motor is located in the center of the plum blossom groove, and the sliding block is rotationally connected to the side wall in the cooling bin. The cooling shovel is located in the cooling bin, a shovel handle of the cooling shovel is in sliding connection with the sliding block and slides along the plum blossom groove through a first pin shaft, one end of the telescopic rod is fixedly connected wit