Abstract: Leather machinery is an important support for the progress of leather industry. The invention of drum is the most important achievement of wet tannery operation to water saving and high efficiency, so that the drum has also become the most critical equipment to complete the chemical process of tanning. Because the circular suspension drum has a fixed moving trajectory, different processing effects of hide or crust need to be changed through the adjustment of the internal structure and operating parameters of the drum. Herein, the common action characteristics of drum on hide or crust were analyzed and some correlations between the internal structure of the drum and the operating parameters of the tanning process were described, which include the influence of the resulting mechanical action such as kneading, extrusion and stretching on the dissolving out of the materials in the hide or crust and the infiltration of the external materials.