Plasticized monofilament absorbable sutures were prepared with poly(p-dioxanone) and poly(p-dioxanone-co-glycolide)．The poly(p-dioxanone) sutures (PDS) with different contents of plasticizer and poly(p-dioxanone-co-glycolide) sutures (PDG) treated under different conditions were analyzed by DSC．The effect of heat treatment temperature on the origin tensile strength

modulus and flexibility were studied

and the degradation properties and strength properties of the two kinds of sutures in vitro hydrolysis were also investigated The results showed that the glass transition temperature (Tg)

crystallization temperature(Tc) and melting point (Tm) of PDS were all lowered with the introduction of plasticizer

while the ability of crystallizatlon was improved、The origin tensile strength and melting heat of PDG were increased withr aising the heat treatment temperature It was found that the retention of tensile strength of PDS and PDG increased first and then decreased with the increase of plasticizer content．while the percentage of weight retention decreased all long in vitro hydrolysis.