<p>Poly-ether-ether-ketone (PEEK) is a high-temperature and chemical resistance non-metal advanced material with exceptional mechanical properties. As a result, it is one of the most suitable materials for fused deposition modeling (FDM) 3D printing. Additionally, PEEK is a thermally induced shape memory polymer (SMP), meaning it can be temporarily shaped at high temperatures and recover its original form when re-heated. This paper explores the shape memory behavior of FDM 3D-printed PEEK, which is the basis for its applications in 4D printing (referred to as 4DP-PEEK). This study not only confirms PEEK’s shape memory properties but also introduces a new method to simulate and control its shape recovery behavior under different thermal conditions. It also investigates the deformation behavior and shape recovery mechanisms of PEEK, providing new insights for future 4D printing technologies. Finite element software Abaqus is used for simulation analysis, and an innovative comprehensive simulation of the 4D printing cycle of PEEK samples is presented. By combining simulations and experiments, the study uncovers the impact of heating temperature and isothermal treatment on the shape memory performance of PEEK and verifies the accuracy of the experimental results. This study demonstrates the significant effect of heating temperature on PEEK’s shape memory behavior, with experiments showing that increasing the heating temperature can significantly enhance the deflection angle of the material (by 300%), providing important guidance for optimizing thermal treatment parameters in the 4D printing process.</p>