Sodium dichloroisocyanurate(DCCNa)is a new type of internal absorption fungicide.It has wide application range,high efficiency and strong biocidal effect.After decades of development,the production technology of DCCNa has been popularized,the products produced by sodium hypochlorite method and trichloroisocyanuric acid double decomposition method are of high quality.The chemical reaction rule of the intermittent sodium hypochlorite method was studied,including the effects of reaction temperature,pH,the material ratio and the difference between low concentration sodium hypochlorite method and high concentration sodium hypochlorite method.　　It was found that the reaction temperature,material ratio and the concentration of sodium hypochlorite solution had a great influence on the reaction results of the sodium hypochlorite method,and the chlorine in the supplementary reaction could increase the product quality to some extent.The final solution is to use a self-made high-concentration sodium hypochlorite solution containing about30％of available chlorine content to supplement the reaction in the presence of chlorine.The optimal reaction temperature is10℃,the ratio of sodiun hypochlorite to cyanuric acid is equal to3.5∶1and the reaction time is20minutes.The highest chlorine content reached the highest grade(62.03％)product yield of57.88％.The production of DCCNa using sodium hypochlorite produces a large amount of mother liquor,which contains many unreacted chlorine,cyanuric acid and sodium hydroxide.The experiment shows that incorporation of10％mother liquor in the reaction solution can make the effective chlorine content of the product reach55.41％,which is close to the qualified product.