In given paper,were studied UV spectra of nanocomposites obtained on base of PP+PbS, PP+CdS ,PP+PbS/CdS and showed that UV absorbtion spectra blue shifted when the dimensions of semiconductor nanoparticles decrase. In this work measured optical band gap for PP/PbS, PP/CdS, PP/PbS/CdS nanocomposites based on PP powder which was treated by electrical discharge during 0.5 hour. SEM analysis of PP + PbS, PP + CdS, PP + PbS /CdS nanocomposites was carried out and it was shown that particle size in nanocomposites was the range of 13-18nm,16-26nm and 9-12 nm in respectively. It has been established that the luminescence of PP + PbS / CdS hybrid nanocomposite has a spectrum of superposition of PbS and CdS spectra, and also has different maximum than the luminescence spectrum of individual nanoparticles. This type of spectrum in mixed systems is associated with the activation of luminescent centers of individual nanoparticles, and also leads to the absorption of luminescence at other wavelengths. Simultaneous decreasing of the particle size also leads to an increase in the band gap, which ultimately results in the slope of the wavelength of the maximum of the luminescence spectrum.