Wick debinding can reduce the debinding cycle time and is a crucial technique in metal powder injection molding (MIM). The porosity of the compact varies locally, but there are few literature reports on determining the porosity distribution of the compact in MIM. The need for measuring porosity distribution motivates this study. A local porosity distribution (LPD) is quoted and measured from the digital image of the pore structure. Applicable LPDs and typical length scales are then calculated by the maximum entropy method. Proper theoretical porosity distribution functions are adopted to fit the applicable LPDs. According to the theoretical distribution function, a random number generator is used to generate data of porosity with quantitative randomness for engineering research. Results indicate that the typical length scale is essential and important for the numerical simulation in determining the size of the control volume (or grid).