A detailed study hay been made on the analytical reaction of some 2,6,7-trihydroxy fluoione derivatives with 73 inorganic ions.The trihydroxyfluorones investigated include three 9-alkyl derivatives and nine 9-aryl derivatives.In 1N sulfuric acid solution, all of the fluorone reagents react with Sb^Ⅲ、Sn^Ⅱ、Sn^Ⅳ、Bi^Ⅲ、Fe^Ⅲ、Ge^Ⅳ、MoO₄⁼、WO₄⁼, forming orange or cherry-red precipitates.The color reaction is particularly sensitive to Sbt11, Snu and Sb^Ⅲ、SnⅡ、Ge^Ⅳ.