(1) (2) Although the absolute number of nitrite content changes in the three pickle jars is different, the overall change trend is basically the same. On the 4th day after curing, the nitrite content in the three pickle tanks reached the peak (the nitrite content inNo. 1, No.2 and No.3 tanks reached 0.60mg/kg, 0.20mg/kg and 0.80mg/kg, respectively), but the nitrite content in pickles began to decrease obviously on the 1st day 10. This may be because the environment in the tank at the beginning of curing is conducive to the reproduction of bacteria (including some nitrate-reducing bacteria), which can promote the reduction of nitrate to nitrite. However, with the extension of curing time, lactic acid bacteria proliferated, which inhibited nitrate-reducing bacteria to some extent, affected their growth and reproduction, and reduced the nitrite content in kimchi again. (3) Among the three pickle jars, the No.2 jar has the least nitrite content, and the No.3 jar has the most nitrite content. The high content of nitrite in Santan is due to the pollution of pickled vegetables during curing. Pay attention to the curing time and control the temperature and salt content in the curing process. When the temperature is too high, the dosage of salt is less than 10%, and the curing time is short, which is easy to cause bacterial reproduction and increase nitrite content.