The present invention relates to a preparation method of a granular oxide adsorbent for water treatment in which a metal oxide is bound to the surface of polymer particles, and more specially, to a preparation method of a granular oxide adsorbent, comprising the following steps: putting polymer particles in an acidic solution; adding polymer particles to a metal oxide aqueous solution and adjusting a pH; and washing and drying the obtained product. Accordingly, a granular oxide adsorbent prepared by the preparation method is provided and is utilized in water treatment and the like.