Objective To study the effects of main gas temperature on speed and temperature of particles under the condition that the powder carrier is at room temperature in high pressure cold spraying. Methods The effects of main gas flow temperature on gas flow field, powder speed and temperature within different pressure differential and different size of nozzle throat were investigated based on numerical simulation of cold spraying field with computational fluid dynamics software Fluent. Results When the pressure differential was 0.1 MPa and the diameter of the nozzle throat was 2 mm, the ratio of the mass flow of powder carrier gas on the total mass flow of the gas in nozzle exceeded 50%. At this time the increasing range of the particles impact velocity and temperature was limited with the increasing of the temperature of main gas. Using nozzle with larger size of throat could weaken the adverse effects effectively of powder carrier gas on particle accelerating. Conclusion The effect of main gas temperature on powder deposition is weakened when the powder carrier gas is considered. In order to improve the powder deposition efficiency, the flow of the powder carrier gas should be as small as possible under the premise of normal powder feeding, and also the nozzle throat diameter should increase appropriately when the nozzle would be designed.