Summarize and analyze the calculation principle of sodium chloride in the current standard of edible salt quality, according to the binding order of the ions in edible salt in the existing standard, the molar mass relationship between calcium ions, magnesium ions and sulphate ions is studied, determine whether consume chlorine ions, the results of final remaining chlorine ions converted into sodium chloride. The calculation of sodium chloride by this method eliminates the calculation process of the content of each impurity compound, which makes the calculation process simple, rapid, accurate and controllable, it is applicable to the calculation of the results in batch inspection and can provide reference for specifying the calculation of sodium chloride results.