Cold spraying, as a new coating process, has attracted worldwide interest for its high deposition efficiency of high-quality metallic coatings. However, a high pressure gas is necessary to accelerate the spray particles to a high velocity through a convergent-divergent de Laval nozzle. Therefore, the gas flow rate is much higher than that used in the conventional thermal spray process. When helium is used as an accelerating gas, the cost will be relatively high. In the present paper, a novel convergent-barrel nozzle was designed through numerical simulation based on the significant influence of particle temperature on its deposition behavior. The effects of the main factors, involving the length of barrel section, the nature of accelerating gas and its operating pressure and temperature, and particle size, were investigated numerically. It was found that the particles can achieve a relatively low velocity but high temperature under a relatively low gas pressure. Therefore, the gas flow rate was significantly reduced. The experiment results with Cu powder confirmed that the particles can be successfully deposited to form a dense coating under a low gas pressure and flow rate.