Aim The effect of oxidized low density lipoprotein （ox-LDL） on proaggregation and proadhesion in human umbilical vein endothelial cells （HUVEC） and the underlying mechanisms were observed. Methods HUVEC in 6-well plate were treated with varied concentrations of ox-LDL （ 50, 100 and 200 mg/L） for 12 h, 24 h and 48 h, respectively. After that, the levels of prostacyclin （PGI2） and thromboxane A2 （TXA2） in supernatants were detected by radioimmunoasssay. Finally, the expression levels of tissue factor （TF）, intercellular cell adhesion molecule-1 （ICAM-1） and vascular cell adhesion molecule-1 （VCAM-1） were examined by Western blot. Results Dose-response assay showed that the proaggregation of HUVEC induced by ox-LDL was enhanced in a concentration-dependent manner by treatment with ox-LDL for 24 h, presenting that the ratios of PGI2/TXA2 markedly decreased （P<0.05 or P<0.01）. The similar results from time-course relationship assay were obtained. In addition, the expression levels of TF significantly increased in a fashion of concentration-dependence. More importantly, the proadhesion of HUVEC was enhanced, displaying the expression levels of ICAM-1 and VCAM-1 were significantly increased in a concentration-dependent fashion. Conclusions ox-LDL enhances the activities of proaggregation and proadhesion in HUVEC in a concentration-dependent manner. The underlying mechanisms might downregulate the value of PGI2/TXA2 and upregulate the expression of TF, ICAM-1 and VCAM-1.