Abstract: Determine the content of calcium with the mixed acidic thionation decomposition sample in the tungsten concentrates mineral.The mineral of tungsten concentrates was decomposed by mixed acidic thionation; severed with tungsten, manganese, iron, zinc etc.; filtered to calcium oxide; dissolved by hydrochloric acid; indicated by calcein-thymolphthalein and determined by EDTA standard solution titration at the PH value>12.Through the trial and practice, this result and national standard method result fit together mutually.With the speedy, simple and accurate quality, this method is available for the anylysis of calsium content in tungsten concentrates mine and tungsten mineral stone.