<p>Injecting water into coal seams with different likelihoods of bursting can weaken the mesoscopic properties of coal mass materials and structures, increase the burst resistance of burst-prone coal masses, and improve the ability of coal seam roadways to block burst stress waves. Dynamic tests were performed on severely and mildly burst-prone coal samples at various moisture contents to study their dynamic characteristics and burst resistance. The attenuation characteristics of stress waves and burst resistance in burst-prone coal masses under different moisture contents were comprehensively assessed. The results suggest that when the burst proneness of coal transitions from a mild state to a severe state, an increase in dynamic strength is observed. Concurrently, the dynamic peak strain and stress wave reflection coefficient decrease, whereas the stress wave transmission coefficient increases. These findings suggest that the capacity of the coal mass to impede stress waves decreases. Increasing the moisture content of the coal mass can linearly enhance its stress wave reflection ability and significantly strengthen the stress wave absorption effect. For severely and mildly burst-prone coal masses, the reflection coefficients increased by 15.22% and 10.69%, respectively, whereas the transmission coefficients decreased by 43.72% and 35.67%, respectively, as the moisture content changed from dry to saturated. The maximum load on the support layer of the severely burst-prone coal mass was 21.33% lower than that of the mildly burst-prone coal mass, and both were lower than the actual support strength, blocking the transfer of dynamic and static loads from coal bursts.</p>