Polylactic acid (PLA) fibers have great potentials in textile fields with eco-friendship and low carbon emission. However, the poor ductility, inferior free radical scavenging effect, and moderate biodegradability make them challenging in qualified fibers. In this context, a series of PLA fibers with excellent free radical scavenging effect were prepared by melt spinning with PLA /poly (ethylene oxide) (PEO) /curcumin (CUR). The tenacity and free radical scavenging effect of the fiber with 12.0 wt.% PEO and 1.0 wt. % CUR were 3.14 CN dtex-1, 96.2% respectively, compared with 2.24 CN dtex-1, 2.9% for pure PLA fibers. X-ray diffraction analysis showed that CUR behaved as nucleating agent and accelerated the crystallization with elevated crystallinity. The synergistic action of PEO and CUR was found to have significant effects on the mechanical, thermal, crystalline, and free radical scavenging properties for the composite fibers. X-photoelectron spectroscopy analysis, morphological investigation, and disintegrability tests in soil demonstrated the homogenous, ductile, and excellent biodegradable behaviors of the as-prepared fibers. The sustainable advantages of the dope-dyed PLA fabrics were also evaluated.