Metal powder injection molding is an important net-shape manufacturing process. Wick debinding is described as fluid transport through a wick bed by capillary action and can shorten the debinding cycle time. The porosity really varies locally, but little research has investigated how the porosity varying with the control volume affects the wick debinding process, as we do in this paper. The present numerical simulation shows the walking flow edges behave randomly, the contours of the wetting wick are irregular and the total debinding time is linearly dependent on the radius of the compact. In addition, an experiment has successfully been developed that can observe the phenomenon of the walking flow edges, measure the total debinding time, and calculate the percentages of residual binder and the pore space filled. The numerical results agree well with the experimental results.