FIELD: physics; chemistry. SUBSTANCE: films of CdPbS substitution solid solutions find wide application in various fields of optoelectronics, including in designs of photoresistors for near infrared range, characterized by high speed and sensitivity, laser equipment, as well as in areas of sensor analytics and solar power engineering. Essence of the proposed method consists in using a method for obtaining CdxPb1-xS films of ion-exchange transformation of CdS films, allowing to increase cadmium content in solid solution composition by treatment of cadmium (II) sulphide (II) films obtained in aqueous solution of lead (II) acetate, as well as their homogenization with subsequent thermal treatment. EFFECT: invention enables to increase the content of cadmium in the solid solution of CdPbS and, in addition, to obtain films which are uniform in composition.