In this paper, we report a novel and facile method of pressure-induced-flow (PIF) processing that remarkably enhanced the mechanical properties of polylactic acid (PLLA)–PEG blends. The impact strength and bending strength increased by about 20 and 4 times, respectively. Meanwhile, the tensile strength and elongation at break were 3 and 7 times higher compared with raw samples. As indicated by DSC and polarizing microscopy, POM, oriented spherulites were present in the sample after PIF processing. The SEM results showed that the fracture surface of the PIF samples became oriented and much rougher. The cell culture results indicated that the PLLA–PEG blends after PIF processing still maintain as good biocompatibility as the original.