Three preparation methods of oxidized starch as dry, semidry and wet process are reviewed and the advantages and disadvantages of them are discussed. The dry process is short in time with low energy consumption per unit product while the production equipments are simple, but the quality of the product is not stable. Semidry process requires more water consumption in production without largely complicating production process while the quality of the product is relatively better. Wet process is the most commonly used method with the merits of uniform reaction, being stable in quality and easy to control, while the shortcomings are the difficulty in retrieving the products, large volumn of water consumption, vast release of sewage presenting as the great pressure on ecological environment. The optimal process condition is prospected based upon the individual pros and cons of three processes for preparing oxidized starch.