To prevent the breaking of buildings in the cryolithozone due to thawing of permafrost soil due to thermal load from these objects, it is necessary to use heat stabilizers. Two-phase passive thermosyphons are widely used among them. To increase the efficiency of such device, a design of a heat stabilizer with a distributed refrigerant supply to the outer surface is proposed. Determining the optimal operating parameters of such device is impossible without a stage of modeling heat and mass transfer. This determines the purpose of the study — the calculation of the temperature distribution in the ground with such heat stabilizer. A calculation is carried out using physico-mathematical model of it with three related tasks: 1) description of the movement of liquid refrigerant through the inner tube of the thermosyphon; 2) calculation of the upward flow of refrigerant in the gap between the outer tube and the segments of the flow separator; 3) calculation of conductive heat transfer in the heat stabilizer-soil system. The modeling is based on the approaches of non-isothermal multiphase mechanics and thermophysics. The temperature profile was calculated in the gap between the flow-separating device consisting of four segments and the heat stabilizer pipe, as well as in the soil at 1 m from the surface of the thermosyphon. The proposed model makes it possible to determine the radial temperature distribution consistent with practical data with an accuracy of 90%. It was found that the use of such separating device can increase the efficiency of reducing soil temperature by 20%.