Abstract: In order to explore application conditions on nitrate reductase,nitrite degradation was the evaluation index. The paper analyzed the optimum conditions of nitrite reductase by single-factors and Design-expert response surface experiments. The impact of Ni Rs was analysis on quality of salted fish through color difference value and sensory indicators. The optimum conditions were enzyme concentration 4mg/m L,reaction temperature34℃,reaction time 5h. The degradation rate of nitrite reached 32.7%. Analysis showed that Ni Rs had no bad effects on the color and sensory of salted fish. Ni Rs had been raised the flavor of salted fish. The results showed that adding Ni Rs to salted fish production would effectively degrade nitrite. It ensured the edible safety of salted fish. The experiments provided theoretical basis and technical support for aquatic products processing.