OBJECTIVE： To study the protective effects of soluble ornithine cyclase activator cinaciguat （called CIN for short） on human umbilical vein endothelial cells （HUVECs） under the condition of high glucose. METHODS： HUVECs were treated with glucose 33.3 mmol/L to induce oxidative stress injury model. HUVECs were divided into normal group， high glucose group and high glucose+CIN 0.01， 0.1， 1 and 10 μmol/L groups. The cell viability was detected by MTT assay， and the survival rate of cells was callulated. Besides， HUVECs were divided into normal group， normal+CIN 1 μmol/L group， high glucose group， high glucose+CIN 1 μmol/L group. MDA content and SOD activity were determined by TBA method and xanthine oxidase method； mRNA expression of ICAM-1 and VCAM-1 were determined by RT-PCR. RESULTS： Compared with normal group， survival rate decreased in high glucose group （P＜0.05）； compared with high glucose group， that increased in high glucose+CIN 0.01， 0.1， 1 and 10 μmol/L groups， in concentration-dependent manner； there was no statistical significance in survival rate between high glucose+CIN 1 μmol/L group and high glucose+CIN 10 μmol/L group （P＞0.05）. Compared with normal group， MDA content and mRNA expression of ICAM-1 and VCAM-1 increased in high glucose group， while SOD activity decreased （P＜0.05）； above indicators had no significant change in normal+CIN 1 μmol/L group （P＞0.05）. Compared with high glucose group， MDA content and mRNA expression of ICAM-1 and  VCAM-1 decreased in high glucose+CIN 1 μmol/L group， while SOD activity increased （P＜0.05） . CONCLUSIONS： CIN can protect high glucose-induced HUVECs injury in vitro. The mechanism may be associated with inhibition of oxidative stress and inflammatory response.