In order to study their nitrite reduction activity and find out the degradation mechanism roughly,two strains of lactic acid bacteria,Lactobacillus plantarum-L134-1-P(LP) and Leuconostoc mesenteroides-L134-1-P(LM),were investigated.It was found that LP had a better ability to degrade nitrite than LM on MRS broth with the addition of nitrite,the final nitrite degradation rate achieved 98.63% and 38.77% respectively.After 72 hours of fermentation,the pH value of LP broth fell to 3.87,the proportion of total acid reached 1.79%.Meanwhile,the pH value of LM broth only reached 5.35,and the proportion of total acid reached 0.34%.It was also shown in SPSS that there was a strong negative correlation between pH and degradation rate,and a positive correlation between total acid and nitrite degradation rate,but viable cell numbers did not have clear relation with nitrite degradation rate.On that basis,we also studied variation trend of nitrite content in deionized water after adding lactic acid.If pH value was adjusted to 3 and the proportion of total acid reached 1.04% in the deionized water,the degradation rate of nitrite would increase efficiently.It reinforces the view that nitrite degradation abilities of lactic acid bacteria mainly depends on acid degradation.