Abstract: The present invention relates to a preparation method for acetylated sodium hyaluronate, which pertains to the field of organic chemical synthesis, characterized in that, the preparation method includes the following steps: in the protective atmosphere of inert gas, subjecting a hyaluronate and an acetic anhydride to a catalytic reaction in an organic solvent with a catalyst added, adding a water absorbent during the reaction, obtaining a reaction liquid, subjecting a reaction liquid to post treatment, separation, purification, and drying to obtain a product. A too high or too low degree of substitution is effectively avoided in the present invention, so as to obtain a product with a degree of substitution of acetyl groups ranging from 2.7 to 3.2, with mild reactive materials and reacting conditions, and simple separation and purification steps.