Shot peening is commonly used as an effective method to extend the service life of parts and reduce the residual tensile stresses. The main principle of this surface treatment method is to introduce compressive residual stresses into parts, thereby preventing the crack-propagation. Water cavitation peening (WCP) is a recent technology that allows generating high-intensity pressure waves and micro-jet at the surface of parts via a cavitating jet. However, it is a challenge to predict the pressure intensity at the treatment surface and therefore being able to make predictive modelization of the process. To anticipate the pressure distribution around the cavitating jet, a multiple steps approach has been developed. First, through the study of a single cavitation bubble, understand the pressure pulse generated by a single bubble during its collapse process. The second step is to establish a numerical simulation of the cavitating jet near the nozzle with ANSYS Fluent. Accordingly, the cavitation area and the vapor volume fraction at different section of cavitating jet will be predicted. Then, the mechanical loading at the surface of parts will be defined by these sources. The second part of the approach is here studied. The simulation results will be compared with experimental high-speed camera imaging of the cavitating jet.