The recovery property of leather after being stretched or bent will decrease over time because of intermolecular interaction, such as hydrogen bonding between collagen fibers. The current methods to improve leather elasticity include chemical-softening which leads to shorter polymer chains and mechanical-shaking which is a merely physical interaction. All these cannot reach an outstanding or durable effect. In this project, a novel polymer with spring-like chains is inserted between the collagen fibers by cross-linking to the active terminal groups of leather. Those chains will work as “spring” to support the fiber network so that the leather can spring back to its original shape after pressure deformation.