Abstract: In order to enhance polyester monofilament cytocompatibility and to meet the need of artificial hair implantation, PPy/PET monofilaments were prepared by liquid in-situ polymerization. The biostability, thermo stability and wearability were tested. The results showed that PPy/PET filaments had better stability in the papain solution and the improvement of temperature could accelerate the degradation; the content of N elements, tensile strength and breaking elongation decreased with the increase of degradation period caused by PPy spalling and surface structure change. The add of PPy improved thermo stability of PET; and the PPy/PET monofilaments with alkali treatment had better wearability.