In this study, the biodegradation behavior of polybutylene succinate (PBS) fibers manufactured to replace conventional nylon-based non-degradable fishing net was observed in seawater environment. In addition, in order to find the appropriate degradation acceleration condition, surfactant addition and UV irradiation were selected as acceleration conditions, and the effects of each condition on the biodegradation behavior of PBS fibers in seawater conditions were confirmed. Despite the 6 months of biodegradation experiments in the seawater environment, negligible weight loss was found, and the degree of biodegradation could be predicted through a decrease in molecular weight and mechanical properties. Meanwhile, the addition of a surfactant facilitated the adsorption of the degraded strain by hydrophilizing the surface of the PBS fiber, which was confirmed to have a great effect on the molecular weight reduction. On the other hand, when ultraviolet irradiation, it was confirmed that fine cracks were generated on the surface of the fibers, thereby clearly deteriorating mechanical strength.