Abstract: To evaluate the role of SUMO-1 in regulating HIF-1 and VEGF after ApoE-/- mice exposed to PM2.5. We investigated SUMOylation of HIF-1 by SUMO-1, and the expression patterns of SUMO-1, HIF-1, and vascular endothelial growth factor (VEGF), a well-characterized target gene of HIF-1, as well as their relationship to each other in aortic arch of mice. ApoE-/- mice was instilled with PM2.5 at dose of 8 mg/kg body weight by intratracheal instillation method. The transcription and expression of SUMO-1 and HIF-1 were detected respectively by QPCR,Western blot. Co-modification of SUMO-1and HIF-1 was determined by CO-IP. After PM2.5 exposure, expression of SUMO-1, HIF-1, VEGF in mouse aorta was up-regulated greatly. CO-IP displayed that SUMO modification of HIF-1 alpha didn’t appeared in control group, while HIF-1 alpha was modified by SUMO-1 after PM2.5 exposure. This work provides PM2.5 exposure may up-regulated expression of SUMO-1, then it stabilized or up-regulated the expression of HIF-1 alpha, enhance the transcriptional activity of HIF-1, and then influence the expression of VEGF.