To reinforce the silk sericin (SS, beta-sheets rich) film, the mixed solution is engineered by molecular network reconstruction with the increase in the wool keratin (WK, alpha-helix rich). Silk sericin demonstrates a transformation from random coil to beta-sheets structure under the influence of glycerol, while the SS and WK composite films reveal the molecular network crossly linked by hydrogen bonds. It is surprising to see that the microstructure transforms from beta-sheet structure to alpha-helix structure with the increase in wool keratin. Furthermore, the alpha-helix in SS-WK composite films can transform to beta-sheets under stretching. Meanwhile, the hydrogen bonds are broken, which give rise to the slippage of molecular chains, and a better flexibility and strain with the increase in keratin contents. Raising the WK ratio increases the absorbance of ultraviolet radiation. These results make them as biomedical applications with controllable properties.