The modeling and simulation activities in the field of high-pressure cold spray can be divided into two main parts: solid mechanics and fluid dynamics. This chapter focuses on these parts of modeling work in cold spray research. The discussion covers the objective, principal concepts, methods, and outcome of modeling and simulation of particle impact and of in-flight history of particles in cold spraying. The concept of integration of particle impact and fluid flow modeling to optimize cold spray deposition for a given material is also explained.