FIELD: chemistry. SUBSTANCE: invention relates to a method for the production of a thin-layer sorbent based on manganese dioxide for alpha-spectrometric detection of alpha-radiating radium isotopes Ra-223, including exposure of film in an acidic solution of potassium permanganate, drying, characterized in that, before exposure, film is treated in a solution of sodium hydroxide at a concentration of 0.5-2 mol/dm³, and polyethylene is used as film material. EFFECT: obtaining a thin-layer sorbent for alpha-spectrometric detection of radium isotopes. 1 cl, 1 dwg, 1 ex.