Abstract: Because the content of fluorine ion in water sample and the content of fluorine ion standard array are very little, collimation error will lead to large relative error to the fluorine ion standard array while compounding every day.Contrast experiments shows that the fluorine ion standard array compounding method can be changed from daily compounding to 20-day compounding and everyday observing.The new fluorine ion standard array compounding method is more stable, easer to repeat and has lower relative error compared with the old one.