Polycrystalline films of CdxPb1-x S (0.021 ≤ x ≤ 0.090) supersaturated substitutional solid solutions with a cubic structure B1 (Fm3¯m space group) have been obtained with varying cadmium acetate salt Cd(CH3COO)2 in the reaction mixture within 0.01-0.1 mol/l on the sitall substrates. Their thickness changed from ~ 0.4 to ~ 1.0 microns. A correlation has been established between the structural-morphological and functional properties of CdxPb1-x S thin-film layers. The extreme character of the voltage sensitivity dependence on the cadmium salt concentration in the reaction bath is associated with the nonmonotonic introduction of cadmium into the PbS crystal lattice. It is shown that the maximum photocurrent is possessed by CdxPb1-x S thin-film layers formed from crystallites with pronounced faceting. We have found the surface sensitivity of the CdxPb1-xS films to the presence of ~ 0.02 mg/m3 NO2 in the air, which is significantly lower than the maximum allowable concentration.