In order to reveal the failure characteristics and mechanical mechanism of pulsed abrasive water jet impacting loaded coal rock. the corresponding numerical model is established by using Smoothed Particle Hydrodynamics-Finite Element Method ( SPH-FEM ). The temporal failure processes of coal and rock under stress-free and two-dimensional stress states impacted by pulsed water jet and pulsed abrasive water jet were compared and analyzed. The influence laws of changes in jet parameters such as pulse amplitude, pulse frequency, and abrasive mass concentration on the failure characteristics of coal and rock under two-dimensional stress were studied. The damage evolution law and stress distribution characteristics of coal rock under non-stress and two-dimensional stress state of pulsed abrasive water jet impact are revealed. The results show that compared with pulsed water jet, pulsed abrasive water jet has higher crushing efficiency, and the application of two-dimensional stress significantly inhibits the formation of crushing pits and the initiation and propagation of internal cracks in coal and rock. With the increase of pulse amplitude, the depth, cross-sectional area of the longitudinal section, and total length of main cracks of coal and rock crushing pits all gradually increase. As pulse frequency or abrasive mass concentration increases, the depth, cross-sectional area of the longitudinal section, and total length of main cracks of coal and rock crushing pits first increase and then decrease. The unit measuring points close to the coal and rock surface exhibit instantaneous damage characteristics, while those far from the surface show stepwise cumulative damage characteristics. Meanwhile, the peak effective stress of different measuring points alternates with time. The loading of two-dimensional stress increases the stress threshold of coal-rock unit failure, thus enhancing the ability of coal-rock to resist damage and failure. The research results provide theoretical guidance for the optimization of process parameters in the impact of loaded coal and rock by pulsed abrasive water jet.