The invention discloses a technique for producing octenyl succinate starch ester with low viscosity by an oxidation method, which comprises steps as follows: waxy rice starch and water are prepared to be starch milk in a reaction vessel, then the starch milk is heated to 34 DEG C to 38 DEG C, and a sodium hydroxide solution is added for adjusting the PH value between 9.3 and 9.7; sodium hypochlorite is added to carry out oxidation reaction, and the PH value and the reaction temperature are kept; sodium pyrosulfite is added to carry out reduction reaction, and a hydrochloride solution is added in the reaction process to adjust the PH value of the starch milk between 8.5 and 9.0, and the temperature is cooled to 28 DEG C to 31 DEG C, and then octenyl succinic anhydride with 2 percent to 3 percent of the total mass of absolute dry starch is added to carry out esterification reaction; and after the esterification reaction, the hydrochloride solution is added to neutralize the PH value of the starch milk between 5.5 and 6.5, and the finished product can be obtained by washing and drying the neutralized starch milk. By adopting the technique for producing the octenyl succinate starch ester with low viscosity by the oxidation method, the product is high in esterification reaction efficiency, good in emulsifying properties and high in product quality.