This part specifies the detection method of fluorine content in bottled water, using flow injection Ion selective electrode method. It is suitable for the determination of fluorine content in bottled drinking water and bottled drinking natural mineral water. First, the sample is diluted and then detected by flow injection Ion selective electrode method. Standard Linear dispersion is established by the linear relationship between electromotive force and negative logarithm value of fluoride ion activity, and then quantified by external standard method. The reagents and materials used include sodium chloride, Sodiumacetate, sodium citrate, acetic acid, total ion strength buffer solution, fluoride ion standard stock solution, current carrier and filter membrane.