Abstract: Protein-Melamine-Trichlorohydrin complex (PMT) with light yellow, is obtained from the polycondensation between melamine and trichlorohydrin with degraded-collagen in anhydrous state. The solubility of PMT amount with 10% PMT solution can achieve 95.2% , and the pH of 10% solution is 6.5 ~7. SDS -PAGE results show that the molecular weight of PMT is between 12~30 kDa, which is larger than degraded-collagen, amino groups of PMT also decreases. The isoelectric point of PMT is pH 5.0 from potentiometric analysis. These two test results demonstrate that degraded -collagen modified successfully. Applying PMT to retanning the blue wet cowhide, the results show that adding PMT in chrome retanning can increase the absorption rate of chromium and improve the physical mechanical properties of leather. The retanned leather will improve the coloring effect as well as the filling of leather