The deposition mechanism of the cold spray (CS) technique is investigated numerically using the smoothed particle hydrodynamics (SPH) method. The CS process is simulated by modeling the impact of a spherical Al-Si powder particle on a mild steel substrate. In this work, the adhesive interaction between the contacting surfaces is described by intersurface forces using the cohesive zone model. Simulation results show that successful bonding is achieved above the critical velocity, but rebound was observed at high velocities. This indicates that optimum deposition is achieved only within a certain range of particle velocities. The simulated deformed particle shape evolution and estimated critical velocity from other sources were compared and good agreement was obtained. The analyses demonstrate the feasibility of the presented SPH methodology and the adhesive interaction model for simulating the deformation behavior of CS particles.