Abstract: In view of the fact that mudstone in mining engineering is frequently situated in a complex “water-dynamic-static” stress environment, this paper aims to reveal the mechanical behavior of mudstone under the sequence of blasting impact followed by loading in diverse water environments. Specifically, static uniaxial compression tests and dynamic-static sequential loading tests are conducted on mudstone specimens with different water contents. The research provides an in-depth analysis of the compressive mechanical properties and failure characteristics of mudstone under different gradients of impact damage and elucidates the cumulative damage evolution laws of moisture-bearing mudstone subjected to impact pre-damage. The results indicate that the peak strength and failure morphology of mudstone are significantly influenced by water content. As the water content increases, a substantial loss in post-peak strength occurs, and the failure mode transitions from typical brittle fracture to ductile deformation. With an increasing number of gradient impacts, a cumulative effect of micro-crack initiation, propagation, and coalescence is observed within the specimens, leading to a reduction in the compressive strength of pre-damaged mudstone, intensified stress drops, and a marked increase in plastic deformation. Notably, compared to the dry state, saturated mudstone exhibits a more significant and rapid decline in strength following impact pre-damage. Regarding the evolution of failure modes, with the increase of impact damage, the failure of dry mudstone gradually shifts from splitting to shearing. Natural mudstone develops multiple main cracks as damage increases, with its failure morphology evolving from single shear to an approximately conical shear pattern. Saturated mudstone, however, generates multiple vertical main cracks and crack clusters, accompanied by localized rock spalling. These conclusions quantitatively characterize the strength degradation features of mudstone under the coupling effect of water and impact, revealing that moisture is the key factor inducing the accelerated evolution of dynamic damage. The research findings provide important theoretical support for the risk assessment and stability control of dynamic disasters in deep water-bearing mudstone engineering.