The effect of particle sizes on the aerosol deposition (AD) of Cu films is investigated in order to understand the deposition behaviors of metal powder during the AD process. The Cu coatings fabricated by using 2 μm Cu powders had a dense microstructure, a high deposition rate (1.6 ± 0.2 μm/min), and low resistance (9.42 ± 0.4 μΩ·cm) compared to that from using Cu powder with a particle size greater than 5 μm. Also, from estimating the internal micro-strain of Cu films, the Cu coatings fabricated by using 2 μm Cu particles exhibited a high micro-strain value of 3.307×10^-3. On the other hand, the strain of Cu coatings fabricated with 5 μm particles was decreased to 2.76×10^-3. These results seem to show that the impacted Cu particles are compressed and flattened by shock waves, and that their bonding is associated with the high internal micro-strain caused by plastic deformation.