In this article is examined the quantitative-qualitative method of evaluation of a degree of radioactive environmental contamination by means of bioaccumulators from of Mosses Class. Is established, that representatives of this Class, possess the increased ability of accumulation for different radionuclides, inclusive of the Cs-137 and Sr-90. On the basis of statistical processing results of the radiological researches, is established, that between the contents of the radionuclides in an environment and their contents in mosses there is a positive correlation that allows to use mosses as quantitativequalitative indicators of radioactive environmental contamination. In article are given empirical formulas for definition of contents Cs-137 and Sr-90 (Bq/kg) in 0-20 cm layer of the untreated soil, proceeding from the contents of these radionuclides in a moss, selected in the given area.