Among the perspective research directions in modern physics, the investigation of amorphous nanostructures plays an important role [1, 2]. The effect of the drop in lattice thermal conductivity in these compounds can be used in thermoelectric applications [3, 4]. Amorphous state of matter is characterized by an atomic structure with the short-range order, as characteristic for crystal structures the long-range order is absent [5, 6]. In this study, we theoretically investigated the phonon transport in amorphous silicon nanowires. Phonon energy dispersions are calculated at various degrees of amorphization in nanowires with dimensions of a few monolayers. Amorphization of nanowire crystal lattices was achieved by varying the parameters of interatomic interactions within the Valence Force Field (VFF) model of crystal lattice vibrations [7, 8]. In the calculation of the energy spectrum of amorphous nanowires, we took into account the following mechanisms of interatomic interactions: the twoparticle "stretching", the three-particle "bending", "stretching-stretching", "stretching-bending" and the four-particle "bending-bending". In Figure 1 we present variation of phonon properties in amorphous silicon nanowires with 8x8 monolayers (ML) square cross-section for different percent of interatomic force constant variation. Change in degree of amorphization of nanowire crystal lattice leads to the substantial change both in phonon density and group velocity for modes with ω > 30 meV. Our calculations show that thermal conductivity of the silicon nanowire with 8x8 ML square cross-section, calculated at room temperature, decreases from ~ 4.5 W/m·K for the crystalline silicon nanowire to ~ 2.8 W/m·K for the amorphous nanowire with amorphization 90 %. The later is explained by the modification of phonon density of states and phonon velocities.