For the first time, pure protein fibers with good mechanical properties were obtained from waste wool after effective de-crosslinking and disentanglement of the highly crosslinked keratin. Every year, more than 1.6 billion pounds of wool keratin-based materials were discarded. Effort has been devoted to convert the keratin resources into high value-added products, especially fibers. In 1940s, pure keratin fibers had been developed from feathers. However, after trying the method, we found the results were not repeatable and did not find any other successful repetition. So far, no effective dissolution and spinning methods have been developed to obtain pure keratin fibers with potential for real applications. In this research, keratin with preserved backbones after de-crosslinking was obtained. Subsequently, surfactant endowed the keratin with satisfactory stretchability for fiber spinning. Fibers of 20 mu m with good tensile strength were successfully developed. The technology could be applied onto other highly crosslinked proteins, including feather keratin from poultry industry, sorghum protein and soy protein in bioenergy co-products for production of various industrial products.