The invention discloses bacteria immobilization particles for water purification and a preparation method of the bacteria immobilization particles, and belongs to the technical field of water treatment. The preparation method comprises the following steps: preparing a bacteria concentrate through flocculation by utilizing activated carbon, diatomite and a chitosan acetic acid solution; adding diatomite, bentonite, silicon dioxide and a polyvinyl alcohol-sodium alginate mixed solution into the concentrate for stirring; carrying out granulation with a granulator to prepare the bacteria immobilization particles. The prepared bacteria immobilization particles are high in biological activity, high in bacteria content (5*10<9>-1*10<10> CFU/g), short in starting time, and high in reaction speed, has a honeycomb structure (100-300 m<2>/g in specific surface area) suitable for bacteria apposition growth and mass transfer, and can be used for immobilizing bacteria for long, prohibiting the invasion of external hazardous materials, and permanently and efficiently treating sewage in different environments and of different water quality types; meanwhile, industrialized production is available for a whole bacteria immobilization particle preparation process, and the prepared bacteria immobilization particles are high in mechanical property, long in service life, and convenient to store and convey.