We used the Monte-Carlo method to analyze the influence of network structure on the propagation law of fluctuating pressure of flow within fractures. A replica of the fracture network was created by numerical simulation, which has resembled statistical characteristics with natural fracture network. Taking the replica of fracture network as main space of fissure water, a one-dimensional transient flow model was established to numerically simulate the propagation of fluctuating pressure. And then, the unsteady time process of fluctuating pressure’s propagation of fissure water and the spatial distribution nephogram of fluctuating intensity were generated. We concluded that the propagation of fluctuating pressure in rock fracture network has significant anisotropy. And the transient fluctuating pressure at any node within fractures is determined by the combination of three factors: the hydro-transient effect of fracture line elements connected with the node(especially of those directly connected with the node), the interfering source at fracture entrances, and the reflection source at fracture ends.