The properties of nanocomposite materials may differ significantly from the properties of bulk materials as well as individual nanoparticles that form the composite. Today nanocomposite materials are considered to be important because on their basis are syntheses new materials with given structural and optical properties, determined by size, shape and ordering of the constituent nanoparticles. In this paper we presents the results of investigation of Gallium Phosphide (GaP) powder nanoparticles (I type) and the same particles in solution (II type), as well as the composite based on the same nanoparticles. The samples of GaP were obtained by colloidal method. Samples of first type was small conglomerates of nanoparticles, and of the second type unstuck individual particles in a colloidal solution. For identification of obtained nanocrystals and it’s size it was used the method of X-ray powder diffraction (Cu anode, λex=0.154 nm) and EDAX. Calculation of approximately dimensions of particles was calculated by Scherrer formula from XRD and it is of about 10 nm. The photoluminescence (PL) of gallium phosphide was excited by YAG:Nd3+(λex1 = 532 nm λex2 =355nm) and nitrogen (N2) (λex3 = 337nm) lasers and studied at room temperature in the wavelength range 350-1000 nm. PL spectra of samples of types I and II contain several peaks in the visible region. All the samples have the same band shape, which may indicate a common nature of radiative transitions. PL intensity is two orders higher in samples of type II. Shape of the curves represents the total PL spectrum of three Gaussian functions with maxima in the spectral regions 2.7eV, 2.9 eV and 3.1 eV. Radiation in the blue-violet region is associated with transitions from the conduction bands in the valence band (Egdir = 2.78 eV, T = 300K). It can be assumed that the broad PL spectrum is caused by the distribution of nanoparticles by size. Comparison of the PL peaks of different samples shows that with decreasing size of nanoparticles GaP photoluminescence band shifts to shorter wavelengths. For ultraviolet radiation λmax1 shifted from 425 to 400 nm and the PL intensity increases with one order. This is a consequence of quantum confinement effect, due to the limited size of the nanoparticle the energy of electrons and holes is quantized, which leads to an increase in the band gap. However, it is impossible to explain such a large shift of the maximum of the luminescence due to quantum confinement effect in the GaP nanoparticles, because that shift can be about a few tenths of eV. Nanocrystals, much like the ideal long-term ordered bulk GaP single crystals, exhibit this huge increase in blue-shifted luminescence due to: (a) negligibly small influence of defects and nonradiative recombination of electron–hole pairs and very high efficiency of their radiative annihilation (b) high perfection of nanocrystal lattice, and (c) high transparency of nanocrystals due to their small dimensions for the light emitted from high points of the GaP Brillouin zones. A significant shift of the maximum PL in violet region and increase its intensity is observed in the spectrum of nanoparticles in the polymer as compared with powder samples. Using the number of polymers in a composite, these effects are amplified. Such a change in the PL spectrum can be explained by assuming of two effects. The composite separates conglomerates of nanoparticles on the individual particles, which leads to increased quantum-confined effects, and small dimensions of the nanocrystals make them transparent for the light emitted from high points of the GaP Brillouin zones.