Abstract: Mercury intrusion porosimetry (MIP) was used to determine the pore content, porosity and bulk density of relimed pelts with different dispersion of collagen fibers and those of pickled pelts with different acid swelling. The MIP results were compared with the micrographs of pelts observed by scanning electron microscope to evaluate whether MIP is suitable for quantitative determination of dispersion and swelling states of hide collagen fibers. The results showed that the pore content and porosity of pelt increased with increasing dispersion degree of relimed pelt or increasing acid swelling degree of pickled pelts, while the bulk density of pelt decreased. Moreover, the MIP displayed better sensitivity and accuracy of detection of pore structure of pelt than scanning electron microscopy. The results suggest that MIP is suitable for quantitative determination of dispersion and swelling degrees of hide collagen fibers.