Abstract: In order to develop a sustained-release solid chlorine dioxide preservative with controlled concentration and effective sterilization time,the effects of different kinds of activators,gels and chloride salts on the concentration and slow release period of chlorine dioxide gas were investigated. The formulation was optimized by L₉(3⁴)orthogonal test design method. The optimized preservative by scanning electron microscopy was observed. The results showed that the use of EDTA as an activator made effective sterilize time over 20%. When sodium carboxymethyl cellulose(CMC)was used as the gel,the sustained-release rate of chlorine dioxide gas was the smallest and the effective sterilization time was longer. The using of NaCl as a chloride salt provided a micro-electric field environment while passivating the reactants. When the mass ratio of CMC,EDTA and NaCl was 14:1:5,the effective sterilization time(concentration of 1~50 mg/kg)of the sustained-release preservative reached 28 d. The internal structure of the preservative agent was observed under the electron microscope. After the formulation optimization,the internal structure of the sustained-release agent was a dense microporous network structure with a tight arrangement of particles and certain rules. The chlorine dioxide gas generated by the reaction was stored in the microporous structure of the sustained-release agent and released slowly.