<p>To improve the crushing efficiency of pulsed jet on hard rock, a pressurized pulsed water jet (PPWJ) technology that can achieve high pulse pressure at low input pressure is proposed. The jet generator was developed by integrating fluid properties and component motions, and a theoretical model was established to calculate the fluid pressurized state. The feasibility of the PPWJ was verified using a self-developed experimental platform. The flow field characteristics of the PPWJ were investigated through a combination of pressure acquisition, high-speed camera imaging, and a modified numerical model. Additionally, the rock-breaking mechanism of the PPWJ was further elucidated through rock-breaking experiments. The results show that by controlling the water inlet pressure, two typical pulse pressure states—fully intermittent and pseudo-intermittent—can be modulated, and pulse pressure and frequency were coupled. Cavitation–vortex interactions are more likely to occur in the fully intermittent state of the PPWJ, which affects the jet stability. The rock-breaking experiments show that the two pulse modes exhibit different rock-breaking effects: fully intermittent PPWJ primarily damages the rock through drilling–spalling, creating large erosion pits on the surface and causing rock fragments to detach, while pseudo-intermittent PPWJ primarily forms small holes through erosion and shearing. Compared with continuous water jet (CWJ) and interrupted pulse water jet (IPWJ), the rock-breaking specific energy consumption of PPWJ is reduced by 60.2% and 54%, respectively, due to its unique generation method, which improves the utilization of jet energy.</p>