Nitrite is poisonous and carcinogenic to people, while nitrate should also be paid attention as the precursor of nitrite. In this study, by fermenting vegetables naturally and fermenting vegetables with specific strains inoculated, the changes of nitrate contents, nitrite contents and total acid contents in vegetables and nitrite contents and pH values in soup were firstly investigated. Correlation analysis of various indicators were further investigated, including the amounts of inoculums, nitrite residues in vegetables, nitrate residues in vegetables and top amounts of nitrite and lowest pH value in soup. Studies showed that nitrite contents in fermented vegetables inoculated with specific strains were lower than those in natural fermentation, while the amounts of nitrate residues were obviously higher. Furthermore, top amounts of nitrite in soup had a remarkable correlation to the amounts of nitrite/nitrate residues in vegetables. The lowest pH values were also closely correlated to the amounts of nitrite residues in vegetables. This study is of great significance to related studies and applications.