Polyethylene terephthalate (PET) fibers are widely used in the preparation of artificial ligaments. However, due to their lack of hydrophilicity, PET fibers have low biocompatibility, which usually results in the poor biological activity of the products. In the present study, in order to improve the hydrophilicity and biocompatibility of PET fibers, we modified their surface using dimethylolpropionic acid (DMPA). Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), tensile testing and cell culture were employed to observe the effects of DMPA modification on the characteristics of the DMPA-PET fibers. In contrast to the original PET fibers, the surface of the DMPA-PET fibers became rough as demonstrated by SEM. The FTIR spectrum further confirmed that a number of hydrophilic groups were formed on the surface of DMPA-PET. However, there were no significant changes in crystallinity and tensile strength between the PET and the DMPA-PET fibers as revealed by DSC and XRD (P>0.05). Finally, the cell co-culture test revealed that the adhesion and proliferation of bone marrow‑derived stromal cells increased greatly on the DMPA-PET fibers compared to those on the original PET fibers (P<0.05). These results demonstrate that DMPA-PET fibers have significant potential as a material for the development of artificial ligaments.