Abstract: Magnesium chloride salt is mainly composed of magnesium chloride，potassium magnesium chloride，and the hydrates thereof，and it also usually contains impurities，such as magnesium oxide，magnesium hydroxide，and magnesium sulfate.The conventional analysis method of magnesium chloride salt is chemical analysis，but it always has two problems：1） As magnesium chloride salt can easily absorb moisture，the quantitative analysis is difficult；2）The analyzed magnesium content of magnesium chloride salt includes the contents of magnesium in magnesium oxide and magnesium hydroxide etc..A comprehensive analysis method that combined X-ray diffraction test with the conventional physical and chemical analysis methods was put forward.Experimental results showed that the method was simple and convenient in operation；its quantitative effect was good，and it could satisfy the demands of industrial production.Therefore，it′s an ideal analysis method.

Key words: magnesium chloride salt, XRD, analysis method