The influence of hydraulic loading within cracks on the evolution mechanism of concrete under dynamic loading was investigated in this paper. Several strain gauges were employed to stick along the crack tip during the experiments. The moving crack tip was captured using these gauges during fracture. In particular, during the stable cracking stage, consistent propagating crack-tip speeds were observed under varying water pressures. Initially, the measured speed measured 2.0 m/s, which later increased to 20.0 m/s. Based on hydraulic experiments, a relationship between the crack tip and the water front was established, allowing the derivation of pressure distribution within crack from experimental data collected under dynamic loading conditions. Furthermore, the fracture parameters, including initial toughness, critical toughness, and cohesive toughness, were calculated for concrete subjected to split loading. The cohesive toughness experienced a 13.9% reduction with the increasing hydraulic pressure to 0.4 MPa, highlighting the deterioration of cohesive fracture toughness due to water infiltration within the concrete crack. This study provides insights to improve the design of civil and hydraulic engineering structures, such as gravity dams.