Objective There are many errors in soil soluble salt and its component formula in published professional books. However, this has not attracted enough attention and no corrections have been made. Such published data may induce wrong results in soil soluble salt and its components calculation and subsequently wrong judgments in the classification or grading of saline-alkali soils.Method 12 professional books published during 2000~2020 and containing 9 indexes (soil soluble salt, CO₃^2–, HCO₃^–, SO₄^2–, Cl^–, K⁺, Na⁺, Ca²⁺, Mg²⁺) were selected for use in deriving their formulas based on related concepts, theoretical basis, experimental principles and experimental methods.Result Results suggested that there were 68 total errors using the 9 indexes. Among the 9 indexes, HCO₃^– recorded the highest frequency of errors, i.e. 11 times and accounted for 16.2%. It is followed by Ca²⁺ which recorded 10 times in total and accounted for 14.7% while soil soluble salt and Cl^– recorded the lowest, i.e. 4 times in total (5.88%). Based on analyses of the characteristics of errors with the 9 indexes, the errors were found to occur as five different aspects categorized as coefficient 2, conversion coefficient, formula, reference and formula unstandard. Out of the five categories, conversion coefficient recorded the highest frequency of errors, i.e. 31 times in total (45.6%); followed by formula at 13 times (19.1%) and the coefficient 2 with the lowest of 4 times (5.88%).Conclusion Errors in soil soluble salt and its component formula were discovered in published data and corrective measures were applied accordingly. The characteristics and causes of errors in calculating the formula of soil soluble salt and its components were suggested. Also, our results suggest reference values for the corrections of relevant formula.