Starch modified with Octenyl Succinic Anhydride is obtained by esterification of OSA and starch. It is often OSA-starch or Starch Sodium Octenyl Succinate. The starch is an excellent modified starch, including the hydrophobic groups of OSA and the hydrophilic groups of starch at the meantime. The research progress of the synthesis and application of starch modified with OSA are introduced, and the development tendencies of OSA-starch are also viewed.