The measurement and predictive functions of the model equation method in the preparation of porous copper were studied. Needlelike and spherical carbamide was used as a space holder with volume content between 10 and 80%. One step of heat treatment for green compacts was applied to fabricate porous copper. A criterion for determining the uniformity of external dimensions of porous copper was proposed. The results showed that the mass follows the law of conservation and the height of porous copper decreased as the increase of spacer content while there was no regularity for the diameter. The porosity of porous copper calculated by the model equation method was equal to those of by the mass volume method. The theoretical formula obtained to describe the relationship between porosity and spacer content of porous copper intersects with the empirical formula. The results indicated that the measurement function of the model equation method was easier to play than the prediction function.