The work deals with the experimental methods of researches of the wave properties of the particles. It was noted that, in the case of large molecules, molecular weight of which exceeds 103 amu, the most adequate is the study of the wave properties of the particles with the help of the interferometer Talbot-Law (ITL). Additional advantages in the interference contrast of the interference picture gives the unification of the ITL with the effect of Kapitza - Dirac - diffraction ofparticles on the standing light wave. The interferometer Kapitza-Dirac-Talbot-Low (IKDTL) allows exploring the wave properties of molecules, molecular weight of which is several thousand amu. Application of this method for the study of the wave properties of the more massive particles is discussed.