Shot peening process is a mechanical surface treatment process widely used in the industry. Ultrasonic shot peening and conventional shot peening are two important mechanisms of this process. This work aims at studying and comparing the influence of conventional shot peening and ultrasonic shot peening on the surface characteristics (residual stresses, equivalent plastic deformations, and roughness). Three-dimensional models are established to simulate the two mechanisms by using the finite elements software ABAQUS/PYTHON. The residual stresses distributions, as well as the roughness and the equivalent plastic deformations of the AISI 2205 and the AISI 316L induced by both models, are predicted and compared.