Aim To investigate the effects of C1q/TNF-related protein 1 (CTRP1) on the expression of adhesion molecules and adhesion function of human umbilical vein endothelial cells(HUVEC) and related mechanisms.Methods HUVEC were cultured and treated with different doses of recombinant CTRP1(0,0,1 000 μg/L). After 24 hours of stimulation, the gene expression and protein expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were detected by Real-time fluorescence quantitative PCR and Western blot respectively. Fluorescence labeled THP-1 monocytes were incubated with HUVEC which were pre-treated with recombinant CTRP1(0,0,1 000 μg/L)or TNF-α(10 μg/L)for 24 h. The number of adhesion monocytes was counted by fluorescent microscope. In in vivo adhesion experiment, recombinant CTRP1 (3 or 10 μg), positive control factor TNF-α (3 μg), or negative control protein bovine serum albumin (BSA) was injected intraperitoneally for 2 h. Real-time monitoring microscopy was used to examine the rolling and adhesion of monocytes to the wall of mesenteric arteries. HUVEC were incubated with recombinant CTRP1(1 000 μg/L) and the expression levels of phospho-p38MAPK,phospho-ERK,phospho-JNK and phospho-p65 were detected by Western blot. Simultaneously, HUVEC pre-treated with SB203580 (the p38MAPK special inhibitor) were incubated with recombinant CTRP1(1 000 μg/L). The expression of adhesion molecules were detected by Western blot. Results After 24 h stimulation with recombinant CTRP1, protein and mRNA levels of adhesion molecules(VCAM-1 and ICAM-1) were significantly increased in a concentration-dependent manner in HUVEC(P＜0.05). CTRP1 dose-dependently induced the adhesion of THP-1 cells to HUVEC in vitro and interactions of leukocytes to the wall of mesenteric arteries in vivo. CTRP1 activated the p38 mitogenprotein kinase(MAPK) pathway with concurrent phosphorylation of the p65 in HUVECs. Consistently administration of p38 inhibitor SB203580,virtually abolished CTRP1-induced expression of VCAM-1 and ICAM-1. Conclusion CTRP1 can induce the expression of VCAM-1 and ICAM-1 in HUVEC and promote the adhesion function of HUVEC through the activation of p38 MAPK signaling pathway.