Abstract: Rock fractures are very important for water storage and movement in Karst regions. We select a typical limestone profile which has vertical and horizontal cross fractures, and conduct an infiltration experiment by a single ring permeameter on the fracture. Firstly, we build a numerical model for the experiment based on Navier-Stokes (N-S) equations. Then use the try-and-error method based on the objective of measured water levels in the single ring to estimate the fracture hydraulic aperture and calculate the proportion of infiltration water in different fractures. We estimate the hydraulic conductivity based on the cubic law, and build another numerical model based on the continuity equation. Finally we compare with the simulation results of two numerical models. The results show that the estimated fracture hydraulic aperture with the N-S method is much less than the measured value; most of water infiltrates along the vertical fracture, but part flows along the lateral fracture; the difference of simulated results between the N-S and cubic law method is not significant, but the fracture infiltration rate estimated with cubic law method is less than that with the N-S method, and N-S method can more accurately describe the process of water movement in fractures.