Abstract: Deep eutectic solvent (DES) aqueous solutions were utilized to extract collagen from deliming cowhide trimmings. The effect of DES type, DES concentration, extraction time and temperature on the collagen extraction efficiency were investigated. Results showed that the optimal extraction efficiency can be obtained by using the DES containing urea and acetic acid as the extraction agent, with the DES concentration of 0.75 mol/L, temperature of 15 ℃ and extraction time of 24 h, respectively. Under this condition, the yield of collagen was 37%; the results of infrared spectroscopy showed that the product held a typical absorption peak of type I collagen. Compared with the collagen extracted by traditional acidic and enzymatic methods, the collagen extracted using DES aqueous solution displayed higher purity of collagen and intact triple helix structure, which endow it with wide potential in biomedical field.