Abstract： Objective To investigate the adhesive and invasive ability of four common periodontal pathogens,Pg33277,Pi25611,Aa29522 and Fn10953 in human umbilical vein endothelial cells(HUVEC).Methods The model of infection of HUVEC by periodontal pathogens was established in vitro.The invasive ability of four periodontal pathogens in HUVEC was tested by scanning electron microscope(SEM)and antibiotic protection assays-colony-forming units(CFU).Results All of the four periodontal pathogens were found to adhere to HUVEC by SEM and invaded HUVEC at invasion numbers of(0.8±0.1)×10~8,(4.1±0.5)×10~6,(1.6±0.3)×10~6 and(5.0±0.4)×10~6 CFU/L respectively by antibiotic protection assays-CFU.The invasion efficiencies were(0.400±0.050)%,(0.021±0.003)%,(0.008±0.002)% and(0.025±0.002)%,respectively.The invasive ability of Pg33277 was significantly greater than those of the other three periodontal pathogens(P＜0.001).There was no difference in invasive abilities among Pi25611,Aa29522 and Fnl0953(P＞0.05).Conclusions All of the four common periodontal pathogens,Pg33277,Pi25611,Aa29522 and Fnl0953 could adhere to and invaded HUVEC,with Pg33277 being the strongest.