The invention relates to a neutron absorption ball preparation method which includes the following steps: the carbon material and neutron absorption material are mixed to form powder material, the powder material is added to the mixed water solution of PVA and PEG under stirring state, boric acid is added to the solution during kneading process to prepare the thickener; the neutron absorption ball is prepared after pre-pressing, extrusion forming, carbonization, cutting, grinding, high temperature treatment and surface packaging treatment. The invention adopts PVA as bonding agent, is environment-friendly and has low price. The extrusion forming technique has high efficiency, low equipment investment and meets the large-scale industrial production requirement.