Abstract: Investigating the microstructure evolution during stress relaxation in springs is of great significance for revealing the underlying relaxation mechanisms, optimizing service conditions, and developing novel spring materials. In this study, the effects of dislocation unpinning and recovery on spring stress relaxation were systematically examined under coupled initial load-temperature conditions, and the post-relaxation microstructure was analyzed. The results indicate that when the initial load is 70% and 80% of the design load and the test temperature is below 393 K, the spring exhibits significant load loss, which is attributed to the weakened pinning effect of Cottrell atmospheres on dislocation motion. When the initial load reaches 90% and 100% of the design load, the load loss of the spring increases with higher test temperatures. Once the initial load exceeds the design load, intermittent relaxation phenomena occur due to the synergistic interaction between dislocation unpinning and recovery. The stress relaxation caused by dislocation motion primarily involves two processes: unpinning and recovery. Dislocation unpinning triggers the transformation from elastic strain to plastic strain, while recovery facilitates the dissipation of plastic strain energy. As the unpinning and recovery processes proceed, the material's microstructure undergoes continuous evolution.