Recent experimental and theoretical investigations of transport in a fracture indicate that fluid flows preferentially through flow channels in the fracture plane. Several one-dimensional (1D) channel models have been introduced to interpret flow and transport through two-dimensional (2D) fractured media. However, those models are not capable of reproducing a tracer breakthrough curve accurately, and the aperture distributions (i.e., aperture mean and standard deviation) predicted by those models cannot characterize flow channels in the fracture. In this paper, we present a new 1D channel model using an inverse algorithm. At a given breakthrough curve, we divide the time domain into a limited number of intervals based on the principle of superposition and then determine aperture distribution of each channel inversely. The new channel model reproduces the tracer breakthrough curve of a fracture almost exactly at a given pressure drop. In addition, the aperture distributions obtained by the new channel model have good agreement with those of 2D modeling of transport in the fracture. In parameter analyses, we found that flow channeling becomes dominant in fracture flow when the coefficient of variation is >0.3. Therefore the new channel model can effectively simulate flow and tracer transport in a fracture in that range.