The ability of human monocyte (MC)to interact with human umbilical vein endothelial cell (VEC) midiated by oxidized low density lipoprotein (OLDL) was determinated by the use of a micromanipulation technique. The ability of polymorphonuclear neutrophil (PMN) was observed at same condition to show the speciality of OLDL’s effect.The results showed that treatment of VEC with OLDL caused a significant increase in critical separation stress (Sc) MC-VEC.contrast, of PMN-VEC was not increased.Treatment of MC and PMN with OLDL caused a repid increase in Sc of MC-VEC and PMN.VEC,the Sc was maximal within 1 hour of exposure to OLDL and decreased in 24 hours.The results suggest that OLDL can enhance MC-VEC interation specially, this effect indicate that OLDL is important factor for the binding of MC to VEC and the entry of MC into the vessel wall in atherosclerotic lesion.