This paper describes the principle of flow-levitation method. An analytical mode l for preparation of nanometal powders in inert gases is presented. Associated w ith the relation between dynamics of gas flow and temperature, the process of th ermal diffusion, nucleation, condensation and crystallization of powders is stud ied. The results of theoretical analysis are in agreement with the practice.It i ndicates that we can control the particle-size distribution by choosing appropri ate characteristic technological parameters.