The invention provides a preparation method of high-purity collagen 
protein sponge, and relates to a preparation method of collagen 
protein sponge. The preparation method of the high-purity collagen 
protein sponge is used for solving the problems that the collagen protein sponge prepared by using a conventional method is long in 
production cycle and low in yield and purity and has poor 
hemostasis performance. The preparation method of the high-purity collagen protein sponge comprises the following steps: step one. pretreating fresh bovine 
heel tendons; step two. extracting collagen protein; step three. centrifuging; step four. 
salting out; step five. dissolving; step six. carrying out gradient 
dialysis; step seven. pre-freezing; step eight. carrying out 
freeze drying; and step nine. sterilizing. The final product prepared by using the method has a smooth and flat surface and relatively good hemostatic performance and is uniform in pore size distribution. The product has relatively high purity (the total amount of amino acids reaches 97.73%), an obvious hemostatic effect and no abnormal taste, is safe, non-toxic, high in yield and short in time; liquid is clear without impurities; the 
production cycle is shortened; the whole preparation process is carried out at a 
room temperature; the 
biological activity of the collagen protein is maintained; and the application of the high-purity collagen protein sponge in clinical is improved.