Abstract: In an acetate buffer medium of pH 4.2 and in the presence of sodium dodecyl sulfate, eosin Y, as a chromogenic reagent, was reacted separately with 5 organotin compounds, namely triphenylchlorostannane (Ⅰ), triphenylhydroxystannane (Ⅱ), tricyclohexylhydroxystannane (Ⅲ), tribenzylchlorostannane (Ⅳ) and dibenzyldichlorostannane (Ⅴ), to form reddish violet colored complexes, with their absorption maxima at 549 nm (for compound Ⅳ) and 544 nm (for the remainders). Linear relationships between values of absorbances and mass conccentrations of the 5 compounds were found in the ranges within 28.9, 22.0, 23.1, 19.2, 33.5 mg·L-1 respectively. Based on these facts, spectrophotometric methods for determination of the 5 organotin compounds using eosin Y as chromogenic reagent were proposed. Values of molar absorptivity (ε546) for the 5 color reaction systems were found to be (4.63, 4.41, 5.09, 4.87, 5.21)×104L·mol-1·cm-1 respectively. Simulated water samples with addition of standard solution of the 5 compounds separately were analyzed by the proposed method, giving results checked quite well with the amounts of standards added. Values of RSD′s (n=5) found were all less than 3%.