The work aims to study the design of adaptive external fixation protective devices for forearm fracture to solve the problem of poor real-time joint of external fixation protective devices for forearm fracture. Design for adaptability (DFAD) and function-behavior-structure model (FBS) were combined to construct a design method of adaptive forearm fracture external fixation protective devices. Combined with the research of intelligent materials and bionic design, the design of adaptive external fixation protective devices for forearm fracture was carried out. Through DFAD-FBS design method, the forearm fracture external fixation protective devices were analyzed. The shape memory polymer of bionic honeycomb structure was applied to the product design of adaptive forearm fracture external fixation protective devices, and the feasibility of product design was verified by finite element analysis and fitting test. The DFAD-FBS design method provides a new design direction to solve the real-time fitting problem of external fixation protective device for forearm fracture. It has certain reference value to solve the design problem of adaptive products, and verifies the feasibility of intelligent materials to solve the fitting of external fixation protective devices for forearm fracture.